diff --git a/spine-ts/main.mjs b/spine-ts/main.mjs
new file mode 100644
index 000000000..54baea9e3
--- /dev/null
+++ b/spine-ts/main.mjs
@@ -0,0 +1,3 @@
+import { SkeletonJson } from "./spine-core/dist/index.js";
+
+console.log(new SkeletonJson());
\ No newline at end of file
diff --git a/spine-ts/package.json b/spine-ts/package.json
index c4cf62668..d7c1dfb56 100644
--- a/spine-ts/package.json
+++ b/spine-ts/package.json
@@ -2,6 +2,7 @@
   "name": "@esotericsoftware/spine-ts",
   "version": "4.1.44",
   "description": "The official Spine Runtimes for the web.",
+  "type": "module",
   "files": [
     "README.md"
   ],
@@ -68,4 +69,4 @@
     "three": "^0.146.0",
     "phaser": "^3.60.0"
   }
-}
+}
\ No newline at end of file
diff --git a/spine-ts/spine-canvas/package.json b/spine-ts/spine-canvas/package.json
index 56c504614..063fee488 100644
--- a/spine-ts/spine-canvas/package.json
+++ b/spine-ts/spine-canvas/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the web.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
diff --git a/spine-ts/spine-canvas/src/AssetManager.ts b/spine-ts/spine-canvas/src/AssetManager.ts
index 2f7b6a562..30870cf1b 100644
--- a/spine-ts/spine-canvas/src/AssetManager.ts
+++ b/spine-ts/spine-canvas/src/AssetManager.ts
@@ -28,7 +28,7 @@
  *****************************************************************************/
 
 import { AssetManagerBase, Downloader } from "@esotericsoftware/spine-core"
-import { CanvasTexture } from "./CanvasTexture";
+import { CanvasTexture } from "./CanvasTexture.js";
 
 export class AssetManager extends AssetManagerBase {
 	constructor (pathPrefix: string = "", downloader: Downloader = new Downloader()) {
diff --git a/spine-ts/spine-canvas/src/SkeletonRenderer.ts b/spine-ts/spine-canvas/src/SkeletonRenderer.ts
index 598873233..2969f3d2d 100644
--- a/spine-ts/spine-canvas/src/SkeletonRenderer.ts
+++ b/spine-ts/spine-canvas/src/SkeletonRenderer.ts
@@ -28,7 +28,7 @@
  *****************************************************************************/
 
 import { Utils, Color, Skeleton, RegionAttachment, BlendMode, MeshAttachment, Slot, TextureRegion, TextureAtlasRegion } from "@esotericsoftware/spine-core";
-import { CanvasTexture } from "./CanvasTexture";
+import { CanvasTexture } from "./CanvasTexture.js";
 
 const worldVertices = Utils.newFloatArray(8);
 
diff --git a/spine-ts/spine-canvas/src/index.ts b/spine-ts/spine-canvas/src/index.ts
index 1c0104b6c..b6568d65a 100644
--- a/spine-ts/spine-canvas/src/index.ts
+++ b/spine-ts/spine-canvas/src/index.ts
@@ -1,4 +1,4 @@
-export * from "./AssetManager";
-export * from "./CanvasTexture";
-export * from "./SkeletonRenderer";
+export * from "./AssetManager.js";
+export * from "./CanvasTexture.js";
+export * from "./SkeletonRenderer.js";
 export * from "@esotericsoftware/spine-core"
\ No newline at end of file
diff --git a/spine-ts/spine-core/package.json b/spine-ts/spine-core/package.json
index 0c1eb19ee..fce974a6a 100644
--- a/spine-ts/spine-core/package.json
+++ b/spine-ts/spine-core/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the web.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
@@ -29,4 +30,4 @@
     "url": "https://github.com/esotericsoftware/spine-runtimes/issues"
   },
   "homepage": "https://github.com/esotericsoftware/spine-runtimes#readme"
-}
+}
\ No newline at end of file
diff --git a/spine-ts/spine-core/src/Animation.ts b/spine-ts/spine-core/src/Animation.ts
index ae4eba9fe..670dd5542 100644
--- a/spine-ts/spine-core/src/Animation.ts
+++ b/spine-ts/spine-core/src/Animation.ts
@@ -27,16 +27,16 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { VertexAttachment, Attachment } from "./attachments/Attachment";
-import { IkConstraint } from "./IkConstraint";
-import { PathConstraint } from "./PathConstraint";
-import { Skeleton } from "./Skeleton";
-import { Slot } from "./Slot";
-import { TransformConstraint } from "./TransformConstraint";
-import { StringSet, Utils, MathUtils, NumberArrayLike } from "./Utils";
-import { Event } from "./Event";
-import { HasTextureRegion } from "./attachments/HasTextureRegion";
-import { SequenceMode, SequenceModeValues } from "./attachments/Sequence";
+import { VertexAttachment, Attachment } from "./attachments/Attachment.js";
+import { IkConstraint } from "./IkConstraint.js";
+import { PathConstraint } from "./PathConstraint.js";
+import { Skeleton } from "./Skeleton.js";
+import { Slot } from "./Slot.js";
+import { TransformConstraint } from "./TransformConstraint.js";
+import { StringSet, Utils, MathUtils, NumberArrayLike } from "./Utils.js";
+import { Event } from "./Event.js";
+import { HasTextureRegion } from "./attachments/HasTextureRegion.js";
+import { SequenceMode, SequenceModeValues } from "./attachments/Sequence.js";
 
 /** A simple container for a list of timelines and a name. */
 export class Animation {
diff --git a/spine-ts/spine-core/src/AnimationState.ts b/spine-ts/spine-core/src/AnimationState.ts
index 155cf5654..9f011f717 100644
--- a/spine-ts/spine-core/src/AnimationState.ts
+++ b/spine-ts/spine-core/src/AnimationState.ts
@@ -27,12 +27,12 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Animation, MixBlend, AttachmentTimeline, MixDirection, RotateTimeline, DrawOrderTimeline, Timeline, EventTimeline } from "./Animation";
-import { AnimationStateData } from "./AnimationStateData";
-import { Skeleton } from "./Skeleton";
-import { Slot } from "./Slot";
-import { StringSet, Pool, Utils, MathUtils } from "./Utils";
-import { Event } from "./Event";
+import { Animation, MixBlend, AttachmentTimeline, MixDirection, RotateTimeline, DrawOrderTimeline, Timeline, EventTimeline } from "./Animation.js";
+import { AnimationStateData } from "./AnimationStateData.js";
+import { Skeleton } from "./Skeleton.js";
+import { Slot } from "./Slot.js";
+import { StringSet, Pool, Utils, MathUtils } from "./Utils.js";
+import { Event } from "./Event.js";
 
 
 /** Applies animations over time, queues animations for later playback, mixes (crossfading) between animations, and applies
diff --git a/spine-ts/spine-core/src/AnimationStateData.ts b/spine-ts/spine-core/src/AnimationStateData.ts
index aee162a49..571b172b3 100644
--- a/spine-ts/spine-core/src/AnimationStateData.ts
+++ b/spine-ts/spine-core/src/AnimationStateData.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Animation } from "./Animation";
-import { SkeletonData } from "./SkeletonData";
-import { StringMap } from "./Utils";
+import { Animation } from "./Animation.js";
+import { SkeletonData } from "./SkeletonData.js";
+import { StringMap } from "./Utils.js";
 
 
 /** Stores mix (crossfade) durations to be applied when {@link AnimationState} animations are changed. */
diff --git a/spine-ts/spine-core/src/AssetManagerBase.ts b/spine-ts/spine-core/src/AssetManagerBase.ts
index 651f3f646..97b3a9bc6 100644
--- a/spine-ts/spine-core/src/AssetManagerBase.ts
+++ b/spine-ts/spine-core/src/AssetManagerBase.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Texture } from "./Texture";
-import { TextureAtlas } from "./TextureAtlas";
-import { Disposable, StringMap } from "./Utils";
+import { Texture } from "./Texture.js";
+import { TextureAtlas } from "./TextureAtlas.js";
+import { Disposable, StringMap } from "./Utils.js";
 
 export class AssetManagerBase implements Disposable {
 	private pathPrefix: string = "";
diff --git a/spine-ts/spine-core/src/AtlasAttachmentLoader.ts b/spine-ts/spine-core/src/AtlasAttachmentLoader.ts
index 5890ba9aa..7c6631dbe 100644
--- a/spine-ts/spine-core/src/AtlasAttachmentLoader.ts
+++ b/spine-ts/spine-core/src/AtlasAttachmentLoader.ts
@@ -27,15 +27,15 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { AttachmentLoader } from "./attachments/AttachmentLoader";
-import { BoundingBoxAttachment } from "./attachments/BoundingBoxAttachment";
-import { ClippingAttachment } from "./attachments/ClippingAttachment";
-import { MeshAttachment } from "./attachments/MeshAttachment";
-import { PathAttachment } from "./attachments/PathAttachment";
-import { PointAttachment } from "./attachments/PointAttachment";
-import { RegionAttachment } from "./attachments/RegionAttachment";
-import { Skin } from "./Skin";
-import { TextureAtlas } from "./TextureAtlas";
+import { AttachmentLoader } from "./attachments/AttachmentLoader.js";
+import { BoundingBoxAttachment } from "./attachments/BoundingBoxAttachment.js";
+import { ClippingAttachment } from "./attachments/ClippingAttachment.js";
+import { MeshAttachment } from "./attachments/MeshAttachment.js";
+import { PathAttachment } from "./attachments/PathAttachment.js";
+import { PointAttachment } from "./attachments/PointAttachment.js";
+import { RegionAttachment } from "./attachments/RegionAttachment.js";
+import { Skin } from "./Skin.js";
+import { TextureAtlas } from "./TextureAtlas.js";
 import { Sequence } from "./attachments/Sequence"
 
 /** An {@link AttachmentLoader} that configures attachments using texture regions from an {@link TextureAtlas}.
diff --git a/spine-ts/spine-core/src/Bone.ts b/spine-ts/spine-core/src/Bone.ts
index ad650bb48..7170d836d 100644
--- a/spine-ts/spine-core/src/Bone.ts
+++ b/spine-ts/spine-core/src/Bone.ts
@@ -27,10 +27,10 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { BoneData, TransformMode } from "./BoneData";
-import { Skeleton } from "./Skeleton";
-import { Updatable } from "./Updatable";
-import { MathUtils, Vector2 } from "./Utils";
+import { BoneData, TransformMode } from "./BoneData.js";
+import { Skeleton } from "./Skeleton.js";
+import { Updatable } from "./Updatable.js";
+import { MathUtils, Vector2 } from "./Utils.js";
 
 /** Stores a bone's current pose.
  *
diff --git a/spine-ts/spine-core/src/BoneData.ts b/spine-ts/spine-core/src/BoneData.ts
index e2b48aea4..bab432378 100644
--- a/spine-ts/spine-core/src/BoneData.ts
+++ b/spine-ts/spine-core/src/BoneData.ts
@@ -27,7 +27,7 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Color } from "./Utils";
+import { Color } from "./Utils.js";
 
 /** Stores the setup pose for a {@link Bone}. */
 export class BoneData {
diff --git a/spine-ts/spine-core/src/Event.ts b/spine-ts/spine-core/src/Event.ts
index 2c7d5a308..1bfc66c89 100644
--- a/spine-ts/spine-core/src/Event.ts
+++ b/spine-ts/spine-core/src/Event.ts
@@ -27,7 +27,7 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { EventData } from "./EventData";
+import { EventData } from "./EventData.js";
 
 /** Stores the current pose values for an {@link Event}.
  *
diff --git a/spine-ts/spine-core/src/IkConstraint.ts b/spine-ts/spine-core/src/IkConstraint.ts
index 80458ffa1..c320d6171 100644
--- a/spine-ts/spine-core/src/IkConstraint.ts
+++ b/spine-ts/spine-core/src/IkConstraint.ts
@@ -27,12 +27,12 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Bone } from "./Bone";
-import { TransformMode } from "./BoneData";
-import { IkConstraintData } from "./IkConstraintData";
-import { Skeleton } from "./Skeleton";
-import { Updatable } from "./Updatable";
-import { MathUtils } from "./Utils";
+import { Bone } from "./Bone.js";
+import { TransformMode } from "./BoneData.js";
+import { IkConstraintData } from "./IkConstraintData.js";
+import { Skeleton } from "./Skeleton.js";
+import { Updatable } from "./Updatable.js";
+import { MathUtils } from "./Utils.js";
 
 /** Stores the current pose for an IK constraint. An IK constraint adjusts the rotation of 1 or 2 constrained bones so the tip of
  * the last bone is as close to the target bone as possible.
diff --git a/spine-ts/spine-core/src/IkConstraintData.ts b/spine-ts/spine-core/src/IkConstraintData.ts
index 90e1d59c5..022dcb807 100644
--- a/spine-ts/spine-core/src/IkConstraintData.ts
+++ b/spine-ts/spine-core/src/IkConstraintData.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { BoneData } from "./BoneData";
-import { ConstraintData } from "./ConstraintData";
+import { BoneData } from "./BoneData.js";
+import { ConstraintData } from "./ConstraintData.js";
 
 
 /** Stores the setup pose for an {@link IkConstraint}.
diff --git a/spine-ts/spine-core/src/PathConstraint.ts b/spine-ts/spine-core/src/PathConstraint.ts
index 765daf279..1b9247b20 100644
--- a/spine-ts/spine-core/src/PathConstraint.ts
+++ b/spine-ts/spine-core/src/PathConstraint.ts
@@ -27,13 +27,13 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { PathAttachment } from "./attachments/PathAttachment";
-import { Bone } from "./Bone";
-import { PathConstraintData, RotateMode, SpacingMode, PositionMode } from "./PathConstraintData";
-import { Skeleton } from "./Skeleton";
-import { Slot } from "./Slot";
-import { Updatable } from "./Updatable";
-import { Utils, MathUtils } from "./Utils";
+import { PathAttachment } from "./attachments/PathAttachment.js";
+import { Bone } from "./Bone.js";
+import { PathConstraintData, RotateMode, SpacingMode, PositionMode } from "./PathConstraintData.js";
+import { Skeleton } from "./Skeleton.js";
+import { Slot } from "./Slot.js";
+import { Updatable } from "./Updatable.js";
+import { Utils, MathUtils } from "./Utils.js";
 
 
 /** Stores the current pose for a path constraint. A path constraint adjusts the rotation, translation, and scale of the
diff --git a/spine-ts/spine-core/src/PathConstraintData.ts b/spine-ts/spine-core/src/PathConstraintData.ts
index 7b3c7307d..ffa65c697 100644
--- a/spine-ts/spine-core/src/PathConstraintData.ts
+++ b/spine-ts/spine-core/src/PathConstraintData.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { BoneData } from "./BoneData";
-import { ConstraintData } from "./ConstraintData";
-import { SlotData } from "./SlotData";
+import { BoneData } from "./BoneData.js";
+import { ConstraintData } from "./ConstraintData.js";
+import { SlotData } from "./SlotData.js";
 
 
 /** Stores the setup pose for a {@link PathConstraint}.
diff --git a/spine-ts/spine-core/src/Skeleton.ts b/spine-ts/spine-core/src/Skeleton.ts
index 5fd2da112..84cc8e030 100644
--- a/spine-ts/spine-core/src/Skeleton.ts
+++ b/spine-ts/spine-core/src/Skeleton.ts
@@ -27,19 +27,19 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Attachment } from "./attachments/Attachment";
-import { MeshAttachment } from "./attachments/MeshAttachment";
-import { PathAttachment } from "./attachments/PathAttachment";
-import { RegionAttachment } from "./attachments/RegionAttachment";
-import { Bone } from "./Bone";
-import { IkConstraint } from "./IkConstraint";
-import { PathConstraint } from "./PathConstraint";
-import { SkeletonData } from "./SkeletonData";
-import { Skin } from "./Skin";
-import { Slot } from "./Slot";
-import { TransformConstraint } from "./TransformConstraint";
-import { Updatable } from "./Updatable";
-import { Color, Utils, MathUtils, Vector2, NumberArrayLike } from "./Utils";
+import { Attachment } from "./attachments/Attachment.js";
+import { MeshAttachment } from "./attachments/MeshAttachment.js";
+import { PathAttachment } from "./attachments/PathAttachment.js";
+import { RegionAttachment } from "./attachments/RegionAttachment.js";
+import { Bone } from "./Bone.js";
+import { IkConstraint } from "./IkConstraint.js";
+import { PathConstraint } from "./PathConstraint.js";
+import { SkeletonData } from "./SkeletonData.js";
+import { Skin } from "./Skin.js";
+import { Slot } from "./Slot.js";
+import { TransformConstraint } from "./TransformConstraint.js";
+import { Updatable } from "./Updatable.js";
+import { Color, Utils, MathUtils, Vector2, NumberArrayLike } from "./Utils.js";
 
 /** Stores the current pose for a skeleton.
  *
diff --git a/spine-ts/spine-core/src/SkeletonBinary.ts b/spine-ts/spine-core/src/SkeletonBinary.ts
index 1c9d0d54a..397d090ad 100644
--- a/spine-ts/spine-core/src/SkeletonBinary.ts
+++ b/spine-ts/spine-core/src/SkeletonBinary.ts
@@ -27,22 +27,22 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Animation, Timeline, AttachmentTimeline, RGBATimeline, RGBTimeline, RGBA2Timeline, RGB2Timeline, AlphaTimeline, RotateTimeline, TranslateTimeline, TranslateXTimeline, TranslateYTimeline, ScaleTimeline, ScaleXTimeline, ScaleYTimeline, ShearTimeline, ShearXTimeline, ShearYTimeline, IkConstraintTimeline, TransformConstraintTimeline, PathConstraintPositionTimeline, PathConstraintSpacingTimeline, PathConstraintMixTimeline, DeformTimeline, DrawOrderTimeline, EventTimeline, CurveTimeline1, CurveTimeline2, CurveTimeline, SequenceTimeline } from "./Animation";
-import { VertexAttachment, Attachment } from "./attachments/Attachment";
-import { AttachmentLoader } from "./attachments/AttachmentLoader";
-import { HasTextureRegion } from "./attachments/HasTextureRegion";
-import { MeshAttachment } from "./attachments/MeshAttachment";
-import { Sequence, SequenceModeValues } from "./attachments/Sequence";
-import { BoneData } from "./BoneData";
-import { Event } from "./Event";
-import { EventData } from "./EventData";
-import { IkConstraintData } from "./IkConstraintData";
-import { PathConstraintData, PositionMode, SpacingMode } from "./PathConstraintData";
-import { SkeletonData } from "./SkeletonData";
-import { Skin } from "./Skin";
-import { SlotData } from "./SlotData";
-import { TransformConstraintData } from "./TransformConstraintData";
-import { Color, Utils } from "./Utils";
+import { Animation, Timeline, AttachmentTimeline, RGBATimeline, RGBTimeline, RGBA2Timeline, RGB2Timeline, AlphaTimeline, RotateTimeline, TranslateTimeline, TranslateXTimeline, TranslateYTimeline, ScaleTimeline, ScaleXTimeline, ScaleYTimeline, ShearTimeline, ShearXTimeline, ShearYTimeline, IkConstraintTimeline, TransformConstraintTimeline, PathConstraintPositionTimeline, PathConstraintSpacingTimeline, PathConstraintMixTimeline, DeformTimeline, DrawOrderTimeline, EventTimeline, CurveTimeline1, CurveTimeline2, CurveTimeline, SequenceTimeline } from "./Animation.js";
+import { VertexAttachment, Attachment } from "./attachments/Attachment.js";
+import { AttachmentLoader } from "./attachments/AttachmentLoader.js";
+import { HasTextureRegion } from "./attachments/HasTextureRegion.js";
+import { MeshAttachment } from "./attachments/MeshAttachment.js";
+import { Sequence, SequenceModeValues } from "./attachments/Sequence.js";
+import { BoneData } from "./BoneData.js";
+import { Event } from "./Event.js";
+import { EventData } from "./EventData.js";
+import { IkConstraintData } from "./IkConstraintData.js";
+import { PathConstraintData, PositionMode, SpacingMode } from "./PathConstraintData.js";
+import { SkeletonData } from "./SkeletonData.js";
+import { Skin } from "./Skin.js";
+import { SlotData } from "./SlotData.js";
+import { TransformConstraintData } from "./TransformConstraintData.js";
+import { Color, Utils } from "./Utils.js";
 
 /** Loads skeleton data in the Spine binary format.
  *
diff --git a/spine-ts/spine-core/src/SkeletonBounds.ts b/spine-ts/spine-core/src/SkeletonBounds.ts
index dc29b41c9..d65393647 100644
--- a/spine-ts/spine-core/src/SkeletonBounds.ts
+++ b/spine-ts/spine-core/src/SkeletonBounds.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { BoundingBoxAttachment } from "./attachments/BoundingBoxAttachment";
-import { Skeleton } from "./Skeleton";
-import { NumberArrayLike, Pool, Utils } from "./Utils";
+import { BoundingBoxAttachment } from "./attachments/BoundingBoxAttachment.js";
+import { Skeleton } from "./Skeleton.js";
+import { NumberArrayLike, Pool, Utils } from "./Utils.js";
 
 /** Collects each visible {@link BoundingBoxAttachment} and computes the world vertices for its polygon. The polygon vertices are
  * provided along with convenience methods for doing hit detection. */
diff --git a/spine-ts/spine-core/src/SkeletonClipping.ts b/spine-ts/spine-core/src/SkeletonClipping.ts
index d9022eb2a..e3beec5aa 100644
--- a/spine-ts/spine-core/src/SkeletonClipping.ts
+++ b/spine-ts/spine-core/src/SkeletonClipping.ts
@@ -27,10 +27,10 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { ClippingAttachment } from "./attachments/ClippingAttachment";
-import { Slot } from "./Slot";
-import { Triangulator } from "./Triangulator";
-import { Utils, Color, NumberArrayLike } from "./Utils";
+import { ClippingAttachment } from "./attachments/ClippingAttachment.js";
+import { Slot } from "./Slot.js";
+import { Triangulator } from "./Triangulator.js";
+import { Utils, Color, NumberArrayLike } from "./Utils.js";
 
 export class SkeletonClipping {
 	private triangulator = new Triangulator();
diff --git a/spine-ts/spine-core/src/SkeletonData.ts b/spine-ts/spine-core/src/SkeletonData.ts
index 19e95b492..0b5de49ef 100644
--- a/spine-ts/spine-core/src/SkeletonData.ts
+++ b/spine-ts/spine-core/src/SkeletonData.ts
@@ -28,13 +28,13 @@
  *****************************************************************************/
 
 import { Animation } from "./Animation"
-import { BoneData } from "./BoneData";
-import { EventData } from "./EventData";
-import { IkConstraintData } from "./IkConstraintData";
-import { PathConstraintData } from "./PathConstraintData";
-import { Skin } from "./Skin";
-import { SlotData } from "./SlotData";
-import { TransformConstraintData } from "./TransformConstraintData";
+import { BoneData } from "./BoneData.js";
+import { EventData } from "./EventData.js";
+import { IkConstraintData } from "./IkConstraintData.js";
+import { PathConstraintData } from "./PathConstraintData.js";
+import { Skin } from "./Skin.js";
+import { SlotData } from "./SlotData.js";
+import { TransformConstraintData } from "./TransformConstraintData.js";
 
 /** Stores the setup pose and all of the stateless data for a skeleton.
  *
diff --git a/spine-ts/spine-core/src/SkeletonJson.ts b/spine-ts/spine-core/src/SkeletonJson.ts
index 818157679..555b3e3df 100644
--- a/spine-ts/spine-core/src/SkeletonJson.ts
+++ b/spine-ts/spine-core/src/SkeletonJson.ts
@@ -27,23 +27,23 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Animation, Timeline, AttachmentTimeline, RGBATimeline, RGBTimeline, AlphaTimeline, RGBA2Timeline, RGB2Timeline, RotateTimeline, TranslateTimeline, TranslateXTimeline, TranslateYTimeline, ScaleTimeline, ScaleXTimeline, ScaleYTimeline, ShearTimeline, ShearXTimeline, ShearYTimeline, IkConstraintTimeline, TransformConstraintTimeline, PathConstraintPositionTimeline, PathConstraintSpacingTimeline, PathConstraintMixTimeline, DeformTimeline, DrawOrderTimeline, EventTimeline, CurveTimeline1, CurveTimeline2, CurveTimeline } from "./Animation";
-import { VertexAttachment, Attachment } from "./attachments/Attachment";
-import { AttachmentLoader } from "./attachments/AttachmentLoader";
-import { MeshAttachment } from "./attachments/MeshAttachment";
-import { BoneData, TransformMode } from "./BoneData";
-import { EventData } from "./EventData";
-import { Event } from "./Event";
-import { IkConstraintData } from "./IkConstraintData";
-import { PathConstraintData, PositionMode, SpacingMode, RotateMode } from "./PathConstraintData";
-import { SkeletonData } from "./SkeletonData";
-import { Skin } from "./Skin";
-import { SlotData, BlendMode } from "./SlotData";
-import { TransformConstraintData } from "./TransformConstraintData";
-import { Utils, Color, NumberArrayLike } from "./Utils";
-import { Sequence, SequenceMode } from "./attachments/Sequence";
-import { SequenceTimeline } from "./Animation";
-import { HasTextureRegion } from "./attachments/HasTextureRegion";
+import { Animation, Timeline, AttachmentTimeline, RGBATimeline, RGBTimeline, AlphaTimeline, RGBA2Timeline, RGB2Timeline, RotateTimeline, TranslateTimeline, TranslateXTimeline, TranslateYTimeline, ScaleTimeline, ScaleXTimeline, ScaleYTimeline, ShearTimeline, ShearXTimeline, ShearYTimeline, IkConstraintTimeline, TransformConstraintTimeline, PathConstraintPositionTimeline, PathConstraintSpacingTimeline, PathConstraintMixTimeline, DeformTimeline, DrawOrderTimeline, EventTimeline, CurveTimeline1, CurveTimeline2, CurveTimeline } from "./Animation.js";
+import { VertexAttachment, Attachment } from "./attachments/Attachment.js";
+import { AttachmentLoader } from "./attachments/AttachmentLoader.js";
+import { MeshAttachment } from "./attachments/MeshAttachment.js";
+import { BoneData, TransformMode } from "./BoneData.js";
+import { EventData } from "./EventData.js";
+import { Event } from "./Event.js";
+import { IkConstraintData } from "./IkConstraintData.js";
+import { PathConstraintData, PositionMode, SpacingMode, RotateMode } from "./PathConstraintData.js";
+import { SkeletonData } from "./SkeletonData.js";
+import { Skin } from "./Skin.js";
+import { SlotData, BlendMode } from "./SlotData.js";
+import { TransformConstraintData } from "./TransformConstraintData.js";
+import { Utils, Color, NumberArrayLike } from "./Utils.js";
+import { Sequence, SequenceMode } from "./attachments/Sequence.js";
+import { SequenceTimeline } from "./Animation.js";
+import { HasTextureRegion } from "./attachments/HasTextureRegion.js";
 
 /** Loads skeleton data in the Spine JSON format.
  *
diff --git a/spine-ts/spine-core/src/Skin.ts b/spine-ts/spine-core/src/Skin.ts
index 6457d43a6..ae5998044 100644
--- a/spine-ts/spine-core/src/Skin.ts
+++ b/spine-ts/spine-core/src/Skin.ts
@@ -27,12 +27,12 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Attachment } from "./attachments/Attachment";
-import { MeshAttachment } from "./attachments/MeshAttachment";
-import { BoneData } from "./BoneData";
-import { ConstraintData } from "./ConstraintData";
-import { Skeleton } from "./Skeleton";
-import { StringMap } from "./Utils";
+import { Attachment } from "./attachments/Attachment.js";
+import { MeshAttachment } from "./attachments/MeshAttachment.js";
+import { BoneData } from "./BoneData.js";
+import { ConstraintData } from "./ConstraintData.js";
+import { Skeleton } from "./Skeleton.js";
+import { StringMap } from "./Utils.js";
 
 /** Stores an entry in the skin consisting of the slot index, name, and attachment **/
 export class SkinEntry {
diff --git a/spine-ts/spine-core/src/Slot.ts b/spine-ts/spine-core/src/Slot.ts
index 0a354da60..263b5c89f 100644
--- a/spine-ts/spine-core/src/Slot.ts
+++ b/spine-ts/spine-core/src/Slot.ts
@@ -27,11 +27,11 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Attachment, VertexAttachment } from "./attachments/Attachment";
-import { Bone } from "./Bone";
-import { Skeleton } from "./Skeleton";
-import { SlotData } from "./SlotData";
-import { Color } from "./Utils";
+import { Attachment, VertexAttachment } from "./attachments/Attachment.js";
+import { Bone } from "./Bone.js";
+import { Skeleton } from "./Skeleton.js";
+import { SlotData } from "./SlotData.js";
+import { Color } from "./Utils.js";
 
 /** Stores a slot's current pose. Slots organize attachments for {@link Skeleton#drawOrder} purposes and provide a place to store
  * state for an attachment. State cannot be stored in an attachment itself because attachments are stateless and may be shared
diff --git a/spine-ts/spine-core/src/SlotData.ts b/spine-ts/spine-core/src/SlotData.ts
index bab2d9011..33388fee0 100644
--- a/spine-ts/spine-core/src/SlotData.ts
+++ b/spine-ts/spine-core/src/SlotData.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { BoneData } from "./BoneData";
-import { Color } from "./Utils";
+import { BoneData } from "./BoneData.js";
+import { Color } from "./Utils.js";
 
 /** Stores the setup pose for a {@link Slot}. */
 export class SlotData {
diff --git a/spine-ts/spine-core/src/TextureAtlas.ts b/spine-ts/spine-core/src/TextureAtlas.ts
index 4aaf6ce1c..74947a2b1 100644
--- a/spine-ts/spine-core/src/TextureAtlas.ts
+++ b/spine-ts/spine-core/src/TextureAtlas.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { AssetManagerBase } from "./AssetManagerBase";
-import { TextureFilter, TextureWrap, Texture, TextureRegion } from "./Texture";
-import { Disposable, Utils, StringMap } from "./Utils";
+import { AssetManagerBase } from "./AssetManagerBase.js";
+import { TextureFilter, TextureWrap, Texture, TextureRegion } from "./Texture.js";
+import { Disposable, Utils, StringMap } from "./Utils.js";
 
 export class TextureAtlas implements Disposable {
 	pages = new Array<TextureAtlasPage>();
diff --git a/spine-ts/spine-core/src/TransformConstraint.ts b/spine-ts/spine-core/src/TransformConstraint.ts
index 7284a9ac3..13f621f53 100644
--- a/spine-ts/spine-core/src/TransformConstraint.ts
+++ b/spine-ts/spine-core/src/TransformConstraint.ts
@@ -27,11 +27,11 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Bone } from "./Bone";
-import { Skeleton } from "./Skeleton";
-import { TransformConstraintData } from "./TransformConstraintData";
-import { Updatable } from "./Updatable";
-import { Vector2, MathUtils } from "./Utils";
+import { Bone } from "./Bone.js";
+import { Skeleton } from "./Skeleton.js";
+import { TransformConstraintData } from "./TransformConstraintData.js";
+import { Updatable } from "./Updatable.js";
+import { Vector2, MathUtils } from "./Utils.js";
 
 
 /** Stores the current pose for a transform constraint. A transform constraint adjusts the world transform of the constrained
diff --git a/spine-ts/spine-core/src/TransformConstraintData.ts b/spine-ts/spine-core/src/TransformConstraintData.ts
index af051517a..a217cbd07 100644
--- a/spine-ts/spine-core/src/TransformConstraintData.ts
+++ b/spine-ts/spine-core/src/TransformConstraintData.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { ConstraintData } from "./ConstraintData";
-import { BoneData } from "./BoneData";
+import { ConstraintData } from "./ConstraintData.js";
+import { BoneData } from "./BoneData.js";
 
 /** Stores the setup pose for a {@link TransformConstraint}.
  *
diff --git a/spine-ts/spine-core/src/Triangulator.ts b/spine-ts/spine-core/src/Triangulator.ts
index a391af981..3508bf688 100644
--- a/spine-ts/spine-core/src/Triangulator.ts
+++ b/spine-ts/spine-core/src/Triangulator.ts
@@ -27,7 +27,7 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { NumberArrayLike, Pool } from "./Utils";
+import { NumberArrayLike, Pool } from "./Utils.js";
 
 export class Triangulator {
 	private convexPolygons = new Array<Array<number>>();
diff --git a/spine-ts/spine-core/src/Utils.ts b/spine-ts/spine-core/src/Utils.ts
index 44e298249..ac9c2758d 100644
--- a/spine-ts/spine-core/src/Utils.ts
+++ b/spine-ts/spine-core/src/Utils.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Skeleton } from "./Skeleton";
-import { MixBlend } from "./Animation";
+import { Skeleton } from "./Skeleton.js";
+import { MixBlend } from "./Animation.js";
 
 export interface StringMap<T> {
 	[key: string]: T;
diff --git a/spine-ts/spine-core/src/attachments/Attachment.ts b/spine-ts/spine-core/src/attachments/Attachment.ts
index a46a2baa4..5a30bd279 100644
--- a/spine-ts/spine-core/src/attachments/Attachment.ts
+++ b/spine-ts/spine-core/src/attachments/Attachment.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Slot } from "../Slot";
-import { NumberArrayLike, Utils } from "../Utils";
+import { Slot } from "../Slot.js";
+import { NumberArrayLike, Utils } from "../Utils.js";
 
 /** The base class for all attachments. */
 export abstract class Attachment {
diff --git a/spine-ts/spine-core/src/attachments/AttachmentLoader.ts b/spine-ts/spine-core/src/attachments/AttachmentLoader.ts
index 04c73948e..054d02374 100644
--- a/spine-ts/spine-core/src/attachments/AttachmentLoader.ts
+++ b/spine-ts/spine-core/src/attachments/AttachmentLoader.ts
@@ -27,14 +27,14 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Skin } from "../Skin";
-import { BoundingBoxAttachment } from "./BoundingBoxAttachment";
-import { ClippingAttachment } from "./ClippingAttachment";
-import { MeshAttachment } from "./MeshAttachment";
-import { PathAttachment } from "./PathAttachment";
-import { PointAttachment } from "./PointAttachment";
-import { RegionAttachment } from "./RegionAttachment";
-import { Sequence } from "./Sequence";
+import { Skin } from "../Skin.js";
+import { BoundingBoxAttachment } from "./BoundingBoxAttachment.js";
+import { ClippingAttachment } from "./ClippingAttachment.js";
+import { MeshAttachment } from "./MeshAttachment.js";
+import { PathAttachment } from "./PathAttachment.js";
+import { PointAttachment } from "./PointAttachment.js";
+import { RegionAttachment } from "./RegionAttachment.js";
+import { Sequence } from "./Sequence.js";
 
 /** The interface which can be implemented to customize creating and populating attachments.
  *
diff --git a/spine-ts/spine-core/src/attachments/BoundingBoxAttachment.ts b/spine-ts/spine-core/src/attachments/BoundingBoxAttachment.ts
index 9733d7301..359903b66 100644
--- a/spine-ts/spine-core/src/attachments/BoundingBoxAttachment.ts
+++ b/spine-ts/spine-core/src/attachments/BoundingBoxAttachment.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Color } from "../Utils";
-import { VertexAttachment, Attachment } from "./Attachment";
+import { Color } from "../Utils.js";
+import { VertexAttachment, Attachment } from "./Attachment.js";
 
 /** An attachment with vertices that make up a polygon. Can be used for hit detection, creating physics bodies, spawning particle
  * effects, and more.
diff --git a/spine-ts/spine-core/src/attachments/ClippingAttachment.ts b/spine-ts/spine-core/src/attachments/ClippingAttachment.ts
index 00bf68fe3..9c9237d5f 100644
--- a/spine-ts/spine-core/src/attachments/ClippingAttachment.ts
+++ b/spine-ts/spine-core/src/attachments/ClippingAttachment.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { SlotData } from "../SlotData";
-import { Color } from "../Utils";
-import { VertexAttachment, Attachment } from "./Attachment";
+import { SlotData } from "../SlotData.js";
+import { Color } from "../Utils.js";
+import { VertexAttachment, Attachment } from "./Attachment.js";
 
 /** An attachment with vertices that make up a polygon used for clipping the rendering of other attachments. */
 export class ClippingAttachment extends VertexAttachment {
diff --git a/spine-ts/spine-core/src/attachments/HasTextureRegion.ts b/spine-ts/spine-core/src/attachments/HasTextureRegion.ts
index 05261d885..8486b0085 100644
--- a/spine-ts/spine-core/src/attachments/HasTextureRegion.ts
+++ b/spine-ts/spine-core/src/attachments/HasTextureRegion.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { TextureRegion } from "../Texture"
-import { Color } from "../Utils"
-import { Sequence } from "./Sequence"
+import { TextureRegion } from "../Texture.js"
+import { Color } from "../Utils.js"
+import { Sequence } from "./Sequence.js"
 
 export interface HasTextureRegion {
 	/** The name used to find the {@link #region()}. */
diff --git a/spine-ts/spine-core/src/attachments/MeshAttachment.ts b/spine-ts/spine-core/src/attachments/MeshAttachment.ts
index 2d959e208..e7caf44ec 100644
--- a/spine-ts/spine-core/src/attachments/MeshAttachment.ts
+++ b/spine-ts/spine-core/src/attachments/MeshAttachment.ts
@@ -27,13 +27,13 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { TextureRegion } from "../Texture";
-import { TextureAtlasRegion } from "../TextureAtlas";
-import { Color, NumberArrayLike, Utils } from "../Utils";
-import { VertexAttachment, Attachment } from "./Attachment";
-import { HasTextureRegion } from "./HasTextureRegion";
-import { Sequence } from "./Sequence";
-import { Slot } from "../Slot";
+import { TextureRegion } from "../Texture.js";
+import { TextureAtlasRegion } from "../TextureAtlas.js";
+import { Color, NumberArrayLike, Utils } from "../Utils.js";
+import { VertexAttachment, Attachment } from "./Attachment.js";
+import { HasTextureRegion } from "./HasTextureRegion.js";
+import { Sequence } from "./Sequence.js";
+import { Slot } from "../Slot.js";
 
 /** An attachment that displays a textured mesh. A mesh has hull vertices and internal vertices within the hull. Holes are not
  * supported. Each vertex has UVs (texture coordinates) and triangles are used to map an image on to the mesh.
diff --git a/spine-ts/spine-core/src/attachments/PathAttachment.ts b/spine-ts/spine-core/src/attachments/PathAttachment.ts
index c6bd9875c..5ec821bf7 100644
--- a/spine-ts/spine-core/src/attachments/PathAttachment.ts
+++ b/spine-ts/spine-core/src/attachments/PathAttachment.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Color, Utils } from "../Utils";
-import { VertexAttachment, Attachment } from "./Attachment";
+import { Color, Utils } from "../Utils.js";
+import { VertexAttachment, Attachment } from "./Attachment.js";
 
 /** An attachment whose vertices make up a composite Bezier curve.
  *
diff --git a/spine-ts/spine-core/src/attachments/PointAttachment.ts b/spine-ts/spine-core/src/attachments/PointAttachment.ts
index 8cd8cf889..c2ee11826 100644
--- a/spine-ts/spine-core/src/attachments/PointAttachment.ts
+++ b/spine-ts/spine-core/src/attachments/PointAttachment.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Bone } from "../Bone";
-import { Color, Vector2, MathUtils } from "../Utils";
-import { VertexAttachment, Attachment } from "./Attachment";
+import { Bone } from "../Bone.js";
+import { Color, Vector2, MathUtils } from "../Utils.js";
+import { VertexAttachment, Attachment } from "./Attachment.js";
 
 /** An attachment which is a single point and a rotation. This can be used to spawn projectiles, particles, etc. A bone can be
  * used in similar ways, but a PointAttachment is slightly less expensive to compute and can be hidden, shown, and placed in a
diff --git a/spine-ts/spine-core/src/attachments/RegionAttachment.ts b/spine-ts/spine-core/src/attachments/RegionAttachment.ts
index 74f1d35d7..69309d95e 100644
--- a/spine-ts/spine-core/src/attachments/RegionAttachment.ts
+++ b/spine-ts/spine-core/src/attachments/RegionAttachment.ts
@@ -27,13 +27,13 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Bone } from "../Bone";
-import { TextureRegion } from "../Texture";
-import { Color, NumberArrayLike, Utils } from "../Utils";
-import { Attachment } from "./Attachment";
-import { HasTextureRegion } from "./HasTextureRegion";
-import { Sequence } from "./Sequence";
-import { Slot } from "../Slot";
+import { Bone } from "../Bone.js";
+import { TextureRegion } from "../Texture.js";
+import { Color, NumberArrayLike, Utils } from "../Utils.js";
+import { Attachment } from "./Attachment.js";
+import { HasTextureRegion } from "./HasTextureRegion.js";
+import { Sequence } from "./Sequence.js";
+import { Slot } from "../Slot.js";
 
 /** An attachment that displays a textured quadrilateral.
  *
@@ -65,7 +65,7 @@ export class RegionAttachment extends Attachment implements HasTextureRegion {
 
 	/** The name of the texture region for this attachment. */
 	path: string;
-	
+
 	region: TextureRegion | null = null;
 	sequence: Sequence | null = null;
 
@@ -194,7 +194,7 @@ export class RegionAttachment extends Attachment implements HasTextureRegion {
 
 	copy (): Attachment {
 		let copy = new RegionAttachment(this.name, this.path);
-		copy.region = this.region;		
+		copy.region = this.region;
 		copy.x = this.x;
 		copy.y = this.y;
 		copy.scaleX = this.scaleX;
diff --git a/spine-ts/spine-core/src/attachments/Sequence.ts b/spine-ts/spine-core/src/attachments/Sequence.ts
index 555f34780..ea8c714f3 100644
--- a/spine-ts/spine-core/src/attachments/Sequence.ts
+++ b/spine-ts/spine-core/src/attachments/Sequence.ts
@@ -27,10 +27,10 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { TextureRegion } from "../Texture";
-import { Slot } from "../Slot";
-import { HasTextureRegion } from "./HasTextureRegion";
-import { Utils } from "../Utils";
+import { TextureRegion } from "../Texture.js";
+import { Slot } from "../Slot.js";
+import { HasTextureRegion } from "./HasTextureRegion.js";
+import { Utils } from "../Utils.js";
 
 
 export class Sequence {
diff --git a/spine-ts/spine-core/src/attachments/index.ts b/spine-ts/spine-core/src/attachments/index.ts
index ef8343420..079a1a54a 100644
--- a/spine-ts/spine-core/src/attachments/index.ts
+++ b/spine-ts/spine-core/src/attachments/index.ts
@@ -1,8 +1,8 @@
-export * from './Attachment';
-export * from './AttachmentLoader';
-export * from './BoundingBoxAttachment';
-export * from './ClippingAttachment';
-export * from './MeshAttachment';
-export * from './PathAttachment';
-export * from './PointAttachment';
-export * from './RegionAttachment';
+export * from './Attachment.js';
+export * from './AttachmentLoader.js';
+export * from './BoundingBoxAttachment.js';
+export * from './ClippingAttachment.js';
+export * from './MeshAttachment.js';
+export * from './PathAttachment.js';
+export * from './PointAttachment.js';
+export * from './RegionAttachment.js';
diff --git a/spine-ts/spine-core/src/index.ts b/spine-ts/spine-core/src/index.ts
index f1104dd34..f656baa4c 100644
--- a/spine-ts/spine-core/src/index.ts
+++ b/spine-ts/spine-core/src/index.ts
@@ -1,39 +1,39 @@
-export * from './Animation';
-export * from './AnimationState';
-export * from './AnimationStateData';
-export * from './AtlasAttachmentLoader';
-export * from './Bone';
-export * from './BoneData';
-export * from './ConstraintData';
-export * from './AssetManagerBase';
-export * from './Event';
-export * from './EventData';
-export * from './IkConstraint';
-export * from './IkConstraintData';
-export * from './PathConstraint';
-export * from './PathConstraintData';
-export * from './Skeleton';
-export * from './SkeletonBinary';
-export * from './SkeletonBounds';
-export * from './SkeletonClipping';
-export * from './SkeletonData';
-export * from './SkeletonJson';
-export * from './Skin';
-export * from './Slot';
-export * from './SlotData';
-export * from './Texture';
-export * from './TextureAtlas';
-export * from './TransformConstraint';
-export * from './TransformConstraintData';
-export * from './Triangulator';
-export * from './Updatable';
-export * from './Utils';
-export * from './polyfills';
-export * from './attachments/Attachment';
-export * from './attachments/AttachmentLoader';
-export * from './attachments/BoundingBoxAttachment';
-export * from './attachments/ClippingAttachment';
-export * from './attachments/MeshAttachment';
-export * from './attachments/PathAttachment';
-export * from './attachments/PointAttachment';
-export * from './attachments/RegionAttachment';
+export * from './Animation.js';
+export * from './AnimationState.js';
+export * from './AnimationStateData.js';
+export * from './AtlasAttachmentLoader.js';
+export * from './Bone.js';
+export * from './BoneData.js';
+export * from './ConstraintData.js';
+export * from './AssetManagerBase.js';
+export * from './Event.js';
+export * from './EventData.js';
+export * from './IkConstraint.js';
+export * from './IkConstraintData.js';
+export * from './PathConstraint.js';
+export * from './PathConstraintData.js';
+export * from './Skeleton.js';
+export * from './SkeletonBinary.js';
+export * from './SkeletonBounds.js';
+export * from './SkeletonClipping.js';
+export * from './SkeletonData.js';
+export * from './SkeletonJson.js';
+export * from './Skin.js';
+export * from './Slot.js';
+export * from './SlotData.js';
+export * from './Texture.js';
+export * from './TextureAtlas.js';
+export * from './TransformConstraint.js';
+export * from './TransformConstraintData.js';
+export * from './Triangulator.js';
+export * from './Updatable.js';
+export * from './Utils.js';
+export * from './polyfills.js';
+export * from './attachments/Attachment.js';
+export * from './attachments/AttachmentLoader.js';
+export * from './attachments/BoundingBoxAttachment.js';
+export * from './attachments/ClippingAttachment.js';
+export * from './attachments/MeshAttachment.js';
+export * from './attachments/PathAttachment.js';
+export * from './attachments/PointAttachment.js';
+export * from './attachments/RegionAttachment.js';
diff --git a/spine-ts/spine-phaser/package.json b/spine-ts/spine-phaser/package.json
index 4672942f1..aa36ea110 100644
--- a/spine-ts/spine-phaser/package.json
+++ b/spine-ts/spine-phaser/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the Phaser.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
diff --git a/spine-ts/spine-phaser/src/SpineGameObject.ts b/spine-ts/spine-phaser/src/SpineGameObject.ts
index c2bd4c787..980732aa5 100644
--- a/spine-ts/spine-phaser/src/SpineGameObject.ts
+++ b/spine-ts/spine-phaser/src/SpineGameObject.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { SPINE_GAME_OBJECT_TYPE } from "./keys";
-import { SpinePlugin } from "./SpinePlugin";
+import { SPINE_GAME_OBJECT_TYPE } from "./keys.js";
+import { SpinePlugin } from "./SpinePlugin.js";
 import {
 	ComputedSizeMixin,
 	DepthMixin,
diff --git a/spine-ts/spine-phaser/src/SpinePlugin.ts b/spine-ts/spine-phaser/src/SpinePlugin.ts
index 446fac955..dcd989301 100644
--- a/spine-ts/spine-phaser/src/SpinePlugin.ts
+++ b/spine-ts/spine-phaser/src/SpinePlugin.ts
@@ -28,9 +28,9 @@
  *****************************************************************************/
 
 import Phaser from "phaser";
-import { SPINE_ATLAS_CACHE_KEY, SPINE_GAME_OBJECT_TYPE, SPINE_SKELETON_DATA_FILE_TYPE, SPINE_ATLAS_FILE_TYPE, SPINE_SKELETON_FILE_CACHE_KEY as SPINE_SKELETON_DATA_CACHE_KEY } from "./keys";
+import { SPINE_ATLAS_CACHE_KEY, SPINE_GAME_OBJECT_TYPE, SPINE_SKELETON_DATA_FILE_TYPE, SPINE_ATLAS_FILE_TYPE, SPINE_SKELETON_FILE_CACHE_KEY as SPINE_SKELETON_DATA_CACHE_KEY } from "./keys.js";
 import { AtlasAttachmentLoader, GLTexture, SceneRenderer, Skeleton, SkeletonBinary, SkeletonData, SkeletonJson, TextureAtlas } from "@esotericsoftware/spine-webgl"
-import { SpineGameObject, SpineGameObjectBoundsProvider } from "./SpineGameObject";
+import { SpineGameObject, SpineGameObjectBoundsProvider } from "./SpineGameObject.js";
 import { CanvasTexture, SkeletonRenderer } from "@esotericsoftware/spine-canvas";
 
 /**
diff --git a/spine-ts/spine-phaser/src/index.ts b/spine-ts/spine-phaser/src/index.ts
index 5ad7c756b..bb43a870d 100644
--- a/spine-ts/spine-phaser/src/index.ts
+++ b/spine-ts/spine-phaser/src/index.ts
@@ -27,17 +27,17 @@
  * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-export * from "./require-shim"
-export * from "./SpinePlugin"
-export * from "./SpineGameObject"
-export * from "./mixins"
+export * from "./require-shim.js"
+export * from "./SpinePlugin.js"
+export * from "./SpineGameObject.js"
+export * from "./mixins.js"
 export * from "@esotericsoftware/spine-core";
 export * from "@esotericsoftware/spine-webgl";
-import { SpineGameObjectConfig, SpinePlugin } from "./SpinePlugin";
+import { SpineGameObjectConfig, SpinePlugin } from "./SpinePlugin.js";
 (window as any).spine = { SpinePlugin: SpinePlugin };
 (window as any)["spine.SpinePlugin"] = SpinePlugin;
 
-import { SpineGameObject, SpineGameObjectBoundsProvider } from "./SpineGameObject";
+import { SpineGameObject, SpineGameObjectBoundsProvider } from "./SpineGameObject.js";
 
 declare global {
 	namespace Phaser.Loader {
diff --git a/spine-ts/spine-pixi/package.json b/spine-ts/spine-pixi/package.json
index 7024d2e90..4099a392e 100644
--- a/spine-ts/spine-pixi/package.json
+++ b/spine-ts/spine-pixi/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the web.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
diff --git a/spine-ts/spine-pixi/src/DarkSlotMesh.ts b/spine-ts/spine-pixi/src/DarkSlotMesh.ts
index 7db9e251e..4a9e02502 100644
--- a/spine-ts/spine-pixi/src/DarkSlotMesh.ts
+++ b/spine-ts/spine-pixi/src/DarkSlotMesh.ts
@@ -27,10 +27,10 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { SpineTexture } from "./SpineTexture";
+import { SpineTexture } from "./SpineTexture.js";
 import type { BlendMode, NumberArrayLike } from "@esotericsoftware/spine-core";
-import { DarkTintMesh } from "./darkTintMesh/DarkTintMesh";
-import type { ISlotMesh } from "./Spine";
+import { DarkTintMesh } from "./darkTintMesh/DarkTintMesh.js";
+import type { ISlotMesh } from "./Spine.js";
 
 export class DarkSlotMesh extends DarkTintMesh implements ISlotMesh {
 	public name: string = "";
diff --git a/spine-ts/spine-pixi/src/SlotMesh.ts b/spine-ts/spine-pixi/src/SlotMesh.ts
index 9b5910223..cafb14981 100644
--- a/spine-ts/spine-pixi/src/SlotMesh.ts
+++ b/spine-ts/spine-pixi/src/SlotMesh.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { SpineTexture } from "./SpineTexture";
+import { SpineTexture } from "./SpineTexture.js";
 import type { BlendMode, NumberArrayLike } from "@esotericsoftware/spine-core";
-import type { ISlotMesh } from "./Spine";
+import type { ISlotMesh } from "./Spine.js";
 import { Mesh, MeshGeometry, MeshMaterial } from "@pixi/mesh";
 import { Texture } from "@pixi/core";
 
diff --git a/spine-ts/spine-pixi/src/assets/atlasLoader.ts b/spine-ts/spine-pixi/src/assets/atlasLoader.ts
index cc008c449..94658d9cd 100644
--- a/spine-ts/spine-pixi/src/assets/atlasLoader.ts
+++ b/spine-ts/spine-pixi/src/assets/atlasLoader.ts
@@ -28,7 +28,7 @@
  *****************************************************************************/
 
 import { TextureAtlas } from "@esotericsoftware/spine-core";
-import { SpineTexture } from "../SpineTexture";
+import { SpineTexture } from "../SpineTexture.js";
 import type { AssetExtension, Loader } from "@pixi/assets";
 import { LoaderParserPriority, checkExtension } from "@pixi/assets";
 import type { Texture } from "@pixi/core";
diff --git a/spine-ts/spine-pixi/src/darkTintMesh/DarkTintMesh.ts b/spine-ts/spine-pixi/src/darkTintMesh/DarkTintMesh.ts
index 9f5efb675..0ab3f49a1 100644
--- a/spine-ts/spine-pixi/src/darkTintMesh/DarkTintMesh.ts
+++ b/spine-ts/spine-pixi/src/darkTintMesh/DarkTintMesh.ts
@@ -29,8 +29,8 @@
 
 import type { Texture, ColorSource, Renderer, BLEND_MODES } from "@pixi/core";
 import { Mesh } from "@pixi/mesh";
-import { DarkTintGeometry } from "./DarkTintGeom";
-import { DarkTintMaterial } from "./DarkTintMaterial";
+import { DarkTintGeometry } from "./DarkTintGeom.js";
+import { DarkTintMaterial } from "./DarkTintMaterial.js";
 
 export interface IDarkTintElement {
 	// eslint-disable-next-line @typescript-eslint/naming-convention
diff --git a/spine-ts/spine-pixi/src/darkTintMesh/DarkTintRenderer.ts b/spine-ts/spine-pixi/src/darkTintMesh/DarkTintRenderer.ts
index 69d78d9ee..edc8504b3 100644
--- a/spine-ts/spine-pixi/src/darkTintMesh/DarkTintRenderer.ts
+++ b/spine-ts/spine-pixi/src/darkTintMesh/DarkTintRenderer.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import type { IDarkTintElement } from "./DarkTintMesh";
-import { DarkTintBatchGeometry } from "./DarkTintBatchGeom";
+import type { IDarkTintElement } from "./DarkTintMesh.js";
+import { DarkTintBatchGeometry } from "./DarkTintBatchGeom.js";
 import type { ExtensionMetadata, Renderer, ViewableBuffer } from "@pixi/core";
 import { BatchRenderer, ExtensionType, BatchShaderGenerator, Color } from "@pixi/core";
 
diff --git a/spine-ts/spine-pixi/src/index.ts b/spine-ts/spine-pixi/src/index.ts
index eaa67acc0..d42128df3 100644
--- a/spine-ts/spine-pixi/src/index.ts
+++ b/spine-ts/spine-pixi/src/index.ts
@@ -27,19 +27,19 @@
  * THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-export * from './require-shim';
-export * from './Spine';
-export * from './SpineDebugRenderer';
-export * from './SpineTexture';
-export * from './SlotMesh';
-export * from './DarkSlotMesh';
-export * from './assets/atlasLoader';
-export * from './assets/skeletonLoader';
-export * from './darkTintMesh/DarkTintBatchGeom';
-export * from './darkTintMesh/DarkTintGeom';
-export * from './darkTintMesh/DarkTintMaterial';
-export * from './darkTintMesh/DarkTintMesh';
-export * from './darkTintMesh/DarkTintRenderer';
+export * from './require-shim.js';
+export * from './Spine.js';
+export * from './SpineDebugRenderer.js';
+export * from './SpineTexture.js';
+export * from './SlotMesh.js';
+export * from './DarkSlotMesh.js';
+export * from './assets/atlasLoader.js';
+export * from './assets/skeletonLoader.js';
+export * from './darkTintMesh/DarkTintBatchGeom.js';
+export * from './darkTintMesh/DarkTintGeom.js';
+export * from './darkTintMesh/DarkTintMaterial.js';
+export * from './darkTintMesh/DarkTintMesh.js';
+export * from './darkTintMesh/DarkTintRenderer.js';
 export * from "@esotericsoftware/spine-core";
 
 
diff --git a/spine-ts/spine-player/package.json b/spine-ts/spine-player/package.json
index ef13eecb0..aff5b22cb 100644
--- a/spine-ts/spine-player/package.json
+++ b/spine-ts/spine-player/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the web.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
diff --git a/spine-ts/spine-player/src/index.ts b/spine-ts/spine-player/src/index.ts
index e6df25d5e..a14abfdf2 100644
--- a/spine-ts/spine-player/src/index.ts
+++ b/spine-ts/spine-player/src/index.ts
@@ -1,3 +1,3 @@
-export * from './Player';
+export * from './Player.js';
 export * from "@esotericsoftware/spine-core";
 export * from "@esotericsoftware/spine-webgl";
\ No newline at end of file
diff --git a/spine-ts/spine-threejs/package.json b/spine-ts/spine-threejs/package.json
index 66b46eb66..7b8014ccc 100644
--- a/spine-ts/spine-threejs/package.json
+++ b/spine-ts/spine-threejs/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the web.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
diff --git a/spine-ts/spine-threejs/src/AssetManager.ts b/spine-ts/spine-threejs/src/AssetManager.ts
index f776832fa..3d6e88cb7 100644
--- a/spine-ts/spine-threejs/src/AssetManager.ts
+++ b/spine-ts/spine-threejs/src/AssetManager.ts
@@ -28,7 +28,7 @@
  *****************************************************************************/
 
 import { AssetManagerBase, Downloader } from "@esotericsoftware/spine-core"
-import { ThreeJsTexture } from "./ThreeJsTexture";
+import { ThreeJsTexture } from "./ThreeJsTexture.js";
 
 export class AssetManager extends AssetManagerBase {
 	constructor (pathPrefix: string = "", downloader: Downloader = new Downloader()) {
diff --git a/spine-ts/spine-threejs/src/MeshBatcher.ts b/spine-ts/spine-threejs/src/MeshBatcher.ts
index c602899a2..7935f03b7 100644
--- a/spine-ts/spine-threejs/src/MeshBatcher.ts
+++ b/spine-ts/spine-threejs/src/MeshBatcher.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { SkeletonMeshMaterial, SkeletonMeshMaterialParametersCustomizer } from "./SkeletonMesh";
+import { SkeletonMeshMaterial, SkeletonMeshMaterialParametersCustomizer } from "./SkeletonMesh.js";
 import * as THREE from "three"
-import { ThreeJsTexture } from "./ThreeJsTexture";
+import { ThreeJsTexture } from "./ThreeJsTexture.js";
 import { BlendMode } from "@esotericsoftware/spine-core";
 
 export class MeshBatcher extends THREE.Mesh {
diff --git a/spine-ts/spine-threejs/src/SkeletonMesh.ts b/spine-ts/spine-threejs/src/SkeletonMesh.ts
index 433c75689..694174851 100644
--- a/spine-ts/spine-threejs/src/SkeletonMesh.ts
+++ b/spine-ts/spine-threejs/src/SkeletonMesh.ts
@@ -43,9 +43,9 @@ import {
 	Utils,
 	Vector2,
 } from "@esotericsoftware/spine-core";
-import { MeshBatcher } from "./MeshBatcher";
+import { MeshBatcher } from "./MeshBatcher.js";
 import * as THREE from "three";
-import { ThreeJsTexture } from "./ThreeJsTexture";
+import { ThreeJsTexture } from "./ThreeJsTexture.js";
 
 export type SkeletonMeshMaterialParametersCustomizer = (
 	materialParameters: THREE.ShaderMaterialParameters
diff --git a/spine-ts/spine-threejs/src/index.ts b/spine-ts/spine-threejs/src/index.ts
index 4e90fc176..441536509 100644
--- a/spine-ts/spine-threejs/src/index.ts
+++ b/spine-ts/spine-threejs/src/index.ts
@@ -1,6 +1,6 @@
-export * from './require-shim';
-export * from './AssetManager';
-export * from './MeshBatcher';
-export * from './SkeletonMesh';
-export * from './ThreeJsTexture';
+export * from './require-shim.js';
+export * from './AssetManager.js';
+export * from './MeshBatcher.js';
+export * from './SkeletonMesh.js';
+export * from './ThreeJsTexture.js';
 export * from "@esotericsoftware/spine-core";
\ No newline at end of file
diff --git a/spine-ts/spine-webgl/package.json b/spine-ts/spine-webgl/package.json
index 2d0194c4c..3e8d4a829 100644
--- a/spine-ts/spine-webgl/package.json
+++ b/spine-ts/spine-webgl/package.json
@@ -4,6 +4,7 @@
   "description": "The official Spine Runtimes for the web.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
+  "type": "module",
   "files": [
     "dist/**/*",
     "README.md",
diff --git a/spine-ts/spine-webgl/src/AssetManager.ts b/spine-ts/spine-webgl/src/AssetManager.ts
index 1a3fd07d1..54ae86e5f 100644
--- a/spine-ts/spine-webgl/src/AssetManager.ts
+++ b/spine-ts/spine-webgl/src/AssetManager.ts
@@ -28,8 +28,8 @@
  *****************************************************************************/
 
 import { AssetManagerBase, Downloader } from "@esotericsoftware/spine-core"
-import { ManagedWebGLRenderingContext } from "./WebGL";
-import { GLTexture } from "./GLTexture";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
+import { GLTexture } from "./GLTexture.js";
 
 
 export class AssetManager extends AssetManagerBase {
diff --git a/spine-ts/spine-webgl/src/Camera.ts b/spine-ts/spine-webgl/src/Camera.ts
index 0cadb1b16..1fb7c78c1 100644
--- a/spine-ts/spine-webgl/src/Camera.ts
+++ b/spine-ts/spine-webgl/src/Camera.ts
@@ -27,8 +27,8 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Matrix4 } from "./Matrix4";
-import { Vector3 } from "./Vector3";
+import { Matrix4 } from "./Matrix4.js";
+import { Vector3 } from "./Vector3.js";
 
 export class OrthoCamera {
 	position = new Vector3(0, 0, 0);
diff --git a/spine-ts/spine-webgl/src/CameraController.ts b/spine-ts/spine-webgl/src/CameraController.ts
index 9c91b84c0..49b7555ba 100644
--- a/spine-ts/spine-webgl/src/CameraController.ts
+++ b/spine-ts/spine-webgl/src/CameraController.ts
@@ -27,9 +27,9 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Input } from "./Input";
-import { OrthoCamera } from "./Camera";
-import { Vector3 } from "./Vector3";
+import { Input } from "./Input.js";
+import { OrthoCamera } from "./Camera.js";
+import { Vector3 } from "./Vector3.js";
 
 export class CameraController {
 	constructor (public canvas: HTMLElement, public camera: OrthoCamera) {
diff --git a/spine-ts/spine-webgl/src/GLTexture.ts b/spine-ts/spine-webgl/src/GLTexture.ts
index ff11e00d8..1385b4888 100644
--- a/spine-ts/spine-webgl/src/GLTexture.ts
+++ b/spine-ts/spine-webgl/src/GLTexture.ts
@@ -28,7 +28,7 @@
  *****************************************************************************/
 
 import { Texture, Disposable, Restorable, TextureFilter, TextureWrap } from "@esotericsoftware/spine-core";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 export class GLTexture extends Texture implements Disposable, Restorable {
 	context: ManagedWebGLRenderingContext;
diff --git a/spine-ts/spine-webgl/src/LoadingScreen.ts b/spine-ts/spine-webgl/src/LoadingScreen.ts
index 27d9af894..30469f651 100644
--- a/spine-ts/spine-webgl/src/LoadingScreen.ts
+++ b/spine-ts/spine-webgl/src/LoadingScreen.ts
@@ -28,8 +28,8 @@
  *****************************************************************************/
 
 import { BlendMode, Color, Disposable, TimeKeeper } from "@esotericsoftware/spine-core";
-import { GLTexture } from "./GLTexture";
-import { ResizeMode, SceneRenderer } from "./SceneRenderer";
+import { GLTexture } from "./GLTexture.js";
+import { ResizeMode, SceneRenderer } from "./SceneRenderer.js";
 
 let spinnerImage: HTMLImageElement;
 let logoImage: HTMLImageElement;
diff --git a/spine-ts/spine-webgl/src/Matrix4.ts b/spine-ts/spine-webgl/src/Matrix4.ts
index 5a13c4682..d33c24b8c 100644
--- a/spine-ts/spine-webgl/src/Matrix4.ts
+++ b/spine-ts/spine-webgl/src/Matrix4.ts
@@ -27,8 +27,7 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Vector2 } from "@esotericsoftware/spine-core";
-import { Vector3 } from "./Vector3";
+import { Vector3 } from "./Vector3.js";
 
 export const M00 = 0;
 export const M01 = 4;
diff --git a/spine-ts/spine-webgl/src/Mesh.ts b/spine-ts/spine-webgl/src/Mesh.ts
index 2080a6780..c47e7274a 100644
--- a/spine-ts/spine-webgl/src/Mesh.ts
+++ b/spine-ts/spine-webgl/src/Mesh.ts
@@ -28,8 +28,8 @@
  *****************************************************************************/
 
 import { Disposable, Restorable } from "@esotericsoftware/spine-core";
-import { Shader } from "./Shader";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { Shader } from "./Shader.js";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 
 export class Mesh implements Disposable, Restorable {
diff --git a/spine-ts/spine-webgl/src/PolygonBatcher.ts b/spine-ts/spine-webgl/src/PolygonBatcher.ts
index 9f869ae3d..c1f733864 100644
--- a/spine-ts/spine-webgl/src/PolygonBatcher.ts
+++ b/spine-ts/spine-webgl/src/PolygonBatcher.ts
@@ -28,10 +28,10 @@
  *****************************************************************************/
 
 import { BlendMode, Disposable } from "@esotericsoftware/spine-core";
-import { GLTexture } from "./GLTexture";
-import { Mesh, Position2Attribute, ColorAttribute, TexCoordAttribute, Color2Attribute } from "./Mesh";
-import { Shader } from "./Shader";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { GLTexture } from "./GLTexture.js";
+import { Mesh, Position2Attribute, ColorAttribute, TexCoordAttribute, Color2Attribute } from "./Mesh.js";
+import { Shader } from "./Shader.js";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 const GL_ONE = 1;
 const GL_ONE_MINUS_SRC_COLOR = 0x0301;
diff --git a/spine-ts/spine-webgl/src/SceneRenderer.ts b/spine-ts/spine-webgl/src/SceneRenderer.ts
index 34ac5d1ec..c4e4c9bc1 100644
--- a/spine-ts/spine-webgl/src/SceneRenderer.ts
+++ b/spine-ts/spine-webgl/src/SceneRenderer.ts
@@ -28,14 +28,14 @@
  *****************************************************************************/
 
 import { Color, Disposable, Skeleton, MathUtils, TextureAtlasRegion } from "@esotericsoftware/spine-core";
-import { OrthoCamera } from "./Camera";
-import { GLTexture } from "./GLTexture";
-import { PolygonBatcher } from "./PolygonBatcher";
-import { Shader } from "./Shader";
-import { ShapeRenderer } from "./ShapeRenderer";
-import { SkeletonDebugRenderer } from "./SkeletonDebugRenderer";
-import { SkeletonRenderer, VertexTransformer } from "./SkeletonRenderer";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { OrthoCamera } from "./Camera.js";
+import { GLTexture } from "./GLTexture.js";
+import { PolygonBatcher } from "./PolygonBatcher.js";
+import { Shader } from "./Shader.js";
+import { ShapeRenderer } from "./ShapeRenderer.js";
+import { SkeletonDebugRenderer } from "./SkeletonDebugRenderer.js";
+import { SkeletonRenderer, VertexTransformer } from "./SkeletonRenderer.js";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 ;
 
 const quad = [
diff --git a/spine-ts/spine-webgl/src/Shader.ts b/spine-ts/spine-webgl/src/Shader.ts
index e6e5ef837..c99502d91 100644
--- a/spine-ts/spine-webgl/src/Shader.ts
+++ b/spine-ts/spine-webgl/src/Shader.ts
@@ -28,7 +28,7 @@
  *****************************************************************************/
 
 import { Disposable, Restorable } from "@esotericsoftware/spine-core";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 export class Shader implements Disposable, Restorable {
 	public static MVP_MATRIX = "u_projTrans";
diff --git a/spine-ts/spine-webgl/src/ShapeRenderer.ts b/spine-ts/spine-webgl/src/ShapeRenderer.ts
index 1bb7c066e..1a5241a07 100644
--- a/spine-ts/spine-webgl/src/ShapeRenderer.ts
+++ b/spine-ts/spine-webgl/src/ShapeRenderer.ts
@@ -28,9 +28,9 @@
  *****************************************************************************/
 
 import { Disposable, Color, Vector2, MathUtils } from "@esotericsoftware/spine-core";
-import { Mesh, Position2Attribute, ColorAttribute } from "./Mesh";
-import { Shader } from "./Shader";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { Mesh, Position2Attribute, ColorAttribute } from "./Mesh.js";
+import { Shader } from "./Shader.js";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 export class ShapeRenderer implements Disposable {
 	private context: ManagedWebGLRenderingContext;
diff --git a/spine-ts/spine-webgl/src/SkeletonDebugRenderer.ts b/spine-ts/spine-webgl/src/SkeletonDebugRenderer.ts
index ed71b5c7a..cb4dfdb0e 100644
--- a/spine-ts/spine-webgl/src/SkeletonDebugRenderer.ts
+++ b/spine-ts/spine-webgl/src/SkeletonDebugRenderer.ts
@@ -28,8 +28,8 @@
  *****************************************************************************/
 
 import { Disposable, Color, SkeletonBounds, Utils, Skeleton, RegionAttachment, MeshAttachment, PathAttachment, ClippingAttachment } from "@esotericsoftware/spine-core";
-import { ShapeRenderer } from "./ShapeRenderer";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { ShapeRenderer } from "./ShapeRenderer.js";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 export class SkeletonDebugRenderer implements Disposable {
 	boneLineColor = new Color(1, 0, 0, 1);
diff --git a/spine-ts/spine-webgl/src/SkeletonRenderer.ts b/spine-ts/spine-webgl/src/SkeletonRenderer.ts
index 034fac2c8..8692c266a 100644
--- a/spine-ts/spine-webgl/src/SkeletonRenderer.ts
+++ b/spine-ts/spine-webgl/src/SkeletonRenderer.ts
@@ -28,9 +28,9 @@
  *****************************************************************************/
 
 import { NumberArrayLike, Color, SkeletonClipping, Vector2, Utils, Skeleton, BlendMode, RegionAttachment, TextureAtlasRegion, MeshAttachment, ClippingAttachment } from "@esotericsoftware/spine-core";
-import { GLTexture } from "./GLTexture";
-import { PolygonBatcher } from "./PolygonBatcher";
-import { ManagedWebGLRenderingContext } from "./WebGL";
+import { GLTexture } from "./GLTexture.js";
+import { PolygonBatcher } from "./PolygonBatcher.js";
+import { ManagedWebGLRenderingContext } from "./WebGL.js";
 
 
 class Renderable {
diff --git a/spine-ts/spine-webgl/src/SpineCanvas.ts b/spine-ts/spine-webgl/src/SpineCanvas.ts
index b200ef893..75ecb5d59 100644
--- a/spine-ts/spine-webgl/src/SpineCanvas.ts
+++ b/spine-ts/spine-webgl/src/SpineCanvas.ts
@@ -27,7 +27,7 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { TimeKeeper, AssetManager, ManagedWebGLRenderingContext, SceneRenderer, Input, StringMap } from "./";
+import { TimeKeeper, AssetManager, ManagedWebGLRenderingContext, SceneRenderer, Input, StringMap } from "./index.js";
 
 /** An app running inside a {@link SpineCanvas}. The app life-cycle
  * is as follows:
diff --git a/spine-ts/spine-webgl/src/Vector3.ts b/spine-ts/spine-webgl/src/Vector3.ts
index aab816c3e..baf741587 100644
--- a/spine-ts/spine-webgl/src/Vector3.ts
+++ b/spine-ts/spine-webgl/src/Vector3.ts
@@ -27,7 +27,7 @@
  * SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *****************************************************************************/
 
-import { Matrix4, M00, M01, M02, M03, M10, M11, M12, M13, M20, M21, M22, M23, M30, M31, M32, M33 } from "./Matrix4";
+import { Matrix4, M00, M01, M02, M03, M10, M11, M12, M13, M20, M21, M22, M23, M30, M31, M32, M33 } from "./Matrix4.js";
 
 export class Vector3 {
 	x = 0;
diff --git a/spine-ts/spine-webgl/src/index.ts b/spine-ts/spine-webgl/src/index.ts
index 6ba803726..f4844d65c 100644
--- a/spine-ts/spine-webgl/src/index.ts
+++ b/spine-ts/spine-webgl/src/index.ts
@@ -1,18 +1,18 @@
-export * from "./AssetManager";
-export * from "./Camera";
-export * from "./CameraController";
-export * from "./GLTexture";
-export * from "./Input";
-export * from "./LoadingScreen";
-export * from "./Matrix4";
-export * from "./Mesh";
-export * from "./PolygonBatcher";
-export * from "./SceneRenderer";
-export * from "./Shader";
-export * from "./ShapeRenderer";
-export * from "./SkeletonDebugRenderer";
-export * from "./SkeletonRenderer";
-export * from "./SpineCanvas";
-export * from "./Vector3";
-export * from "./WebGL";
+export * from "./AssetManager.js";
+export * from "./Camera.js";
+export * from "./CameraController.js";
+export * from "./GLTexture.js";
+export * from "./Input.js";
+export * from "./LoadingScreen.js";
+export * from "./Matrix4.js";
+export * from "./Mesh.js";
+export * from "./PolygonBatcher.js";
+export * from "./SceneRenderer.js";
+export * from "./Shader.js";
+export * from "./ShapeRenderer.js";
+export * from "./SkeletonDebugRenderer.js";
+export * from "./SkeletonRenderer.js";
+export * from "./SpineCanvas.js";
+export * from "./Vector3.js";
+export * from "./WebGL.js";
 export * from "@esotericsoftware/spine-core";
\ No newline at end of file
diff --git a/spine-ts/tsconfig.base.json b/spine-ts/tsconfig.base.json
index 0100a44de..11320c84f 100644
--- a/spine-ts/tsconfig.base.json
+++ b/spine-ts/tsconfig.base.json
@@ -1,7 +1,7 @@
 {
 	"compilerOptions": {
-		"module": "es2015",
-		"target": "ES6",
+		"target": "ESNext",
+		"module": "ESNext",
 		"noImplicitAny": true,
 		"preserveConstEnums": true,
 		"inlineSourceMap": true,
@@ -14,6 +14,6 @@
 		"declaration": true,
 		"composite": true,
 		"moduleResolution": "node",
-		"strict": true
+		"strict": true,
 	}
 }
\ No newline at end of file