diff --git a/src/types/git.ts b/__tests__/.helpers/os.ts
similarity index 55%
rename from src/types/git.ts
rename to __tests__/.helpers/os.ts
index 47cd3d0e..0f2f770c 100644
--- a/src/types/git.ts
+++ b/__tests__/.helpers/os.ts
@@ -1,5 +1,5 @@
 /**
- * Copyright 2023 actions-toolkit authors
+ * Copyright 2025 actions-toolkit authors
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,6 +14,17 @@
  * limitations under the License.
  */
 
-import {Context as GitHubContext} from '@actions/github/lib/context';
+import {jest} from '@jest/globals';
+import os from 'os';
 
-export type Context = GitHubContext;
+export const mockPlatform = (platform: NodeJS.Platform) => {
+  return jest.spyOn(os, 'platform').mockImplementation(() => platform);
+};
+
+export const mockArch = (arch: string) => {
+  return jest.spyOn(os, 'arch').mockImplementation(() => arch);
+};
+
+export const mockHomedir = (dir: string) => {
+  return jest.spyOn(os, 'homedir').mockImplementation(() => dir);
+};
diff --git a/__tests__/buildx/install.test.ts b/__tests__/buildx/install.test.ts
index 9defe183..fcfa3112 100644
--- a/__tests__/buildx/install.test.ts
+++ b/__tests__/buildx/install.test.ts
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import {describe, expect, it, jest, test, afterEach} from '@jest/globals';
+import {describe, expect, it, test, afterEach} from '@jest/globals';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {Install} from '../../src/buildx/install';
 
@@ -85,8 +86,8 @@ describe('download', () => {
     ['linux', 's390x'],
   ])(
   'acquires buildx for %s/%s', async (os, arch) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => os as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => arch);
+    mockPlatform(os as NodeJS.Platform);
+    mockArch(arch);
     const install = new Install();
     const buildxBin = await install.download('latest');
     expect(fs.existsSync(buildxBin)).toBe(true);
diff --git a/__tests__/compose/install.test.ts b/__tests__/compose/install.test.ts
index c87ea0cd..b50da2c7 100644
--- a/__tests__/compose/install.test.ts
+++ b/__tests__/compose/install.test.ts
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import {describe, expect, it, jest, test, afterEach} from '@jest/globals';
+import {describe, expect, it, test, afterEach} from '@jest/globals';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {Install} from '../../src/compose/install';
 
@@ -85,8 +86,8 @@ describe('download', () => {
     ['linux', 's390x'],
   ])(
   'acquires compose for %s/%s', async (os, arch) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => os as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => arch);
+    mockPlatform(os as NodeJS.Platform);
+    mockArch(arch);
     const install = new Install();
     const composeBin = await install.download('latest');
     expect(fs.existsSync(composeBin)).toBe(true);
diff --git a/__tests__/cosign/install.test.ts b/__tests__/cosign/install.test.ts
index f77fe10b..4a97fc80 100644
--- a/__tests__/cosign/install.test.ts
+++ b/__tests__/cosign/install.test.ts
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import {describe, expect, it, jest, test, afterEach} from '@jest/globals';
+import {describe, expect, it, test, afterEach} from '@jest/globals';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {Install} from '../../src/cosign/install';
 
@@ -80,8 +81,8 @@ describe('download', () => {
     ['linux', 'arm64']
   ])(
   'acquires undock for %s/%s', async (os, arch) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => os as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => arch);
+    mockPlatform(os as NodeJS.Platform);
+    mockArch(arch);
     const install = new Install();
     const cosignBin = await install.download({
       version: 'latest'
diff --git a/__tests__/docker/docker.test.ts b/__tests__/docker/docker.test.ts
index c0bd65a2..483c52a5 100644
--- a/__tests__/docker/docker.test.ts
+++ b/__tests__/docker/docker.test.ts
@@ -19,9 +19,10 @@ import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as io from '@actions/io';
-import osm = require('os');
 import * as rimraf from 'rimraf';
 
+import {mockHomedir} from '../.helpers/os';
+
 import {Docker} from '../../src/docker/docker';
 
 import {ConfigFile} from '../../src/types/docker/docker';
@@ -47,7 +48,7 @@ describe('configDir', () => {
   });
   it('returns default', async () => {
     process.env.DOCKER_CONFIG = '';
-    jest.spyOn(osm, 'homedir').mockImplementation(() => path.join('/tmp', 'home'));
+    mockHomedir(path.join('/tmp', 'home'));
     expect(Docker.configDir).toEqual(path.join('/tmp', 'home', '.docker'));
   });
   it('returns from env', async () => {
diff --git a/__tests__/docker/install.test.ts b/__tests__/docker/install.test.ts
index 7b1d1ce3..aebec663 100644
--- a/__tests__/docker/install.test.ts
+++ b/__tests__/docker/install.test.ts
@@ -19,7 +19,8 @@ import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {Install, InstallSourceArchive, InstallSourceImage} from '../../src/docker/install';
 
@@ -60,8 +61,8 @@ describe('download', () => {
     [image('27.3.1'), 'win32'],
   ])(
   'acquires %p of docker (%s)', async (source, platformOS) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => platformOS as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => 'x64');
+    mockPlatform(platformOS as NodeJS.Platform);
+    mockArch('x64');
     const install = new Install({
       source: source,
       runDir: tmpDir
diff --git a/__tests__/oci/oci.test.ts b/__tests__/oci/oci.test.ts
index 684f88fe..0125ee73 100644
--- a/__tests__/oci/oci.test.ts
+++ b/__tests__/oci/oci.test.ts
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import {afterEach, describe, expect, jest, test} from '@jest/globals';
+import {afterEach, describe, expect, test} from '@jest/globals';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {OCI} from '../../src/oci/oci';
 
@@ -44,8 +45,8 @@ describe('defaultPlatform', () => {
     ['linux', 'ppc64', {architecture: 'ppc64le', os: 'linux'}],
     ['linux', 's390x', {architecture: 's390x', os: 'linux'}]
   ])('default platform for %s/%s', async (os: string, arch: string, expected: Platform) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => os as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => arch);
+    mockPlatform(os as NodeJS.Platform);
+    mockArch(arch);
     const res = OCI.defaultPlatform();
     expect(res).toEqual(expected);
   });
diff --git a/__tests__/regclient/install.test.ts b/__tests__/regclient/install.test.ts
index 132fd7a0..90733a88 100644
--- a/__tests__/regclient/install.test.ts
+++ b/__tests__/regclient/install.test.ts
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import {describe, expect, it, jest, test, afterEach} from '@jest/globals';
+import {describe, expect, it, test, afterEach} from '@jest/globals';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {Install} from '../../src/regclient/install';
 
@@ -75,8 +76,8 @@ describe('download', () => {
     ['linux', 's390x'],
   ])(
   'acquires regclient for %s/%s', async (os, arch) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => os as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => arch);
+    mockPlatform(os as NodeJS.Platform);
+    mockArch(arch);
     const install = new Install();
     const regclientBin = await install.download('latest');
     expect(fs.existsSync(regclientBin)).toBe(true);
diff --git a/__tests__/testResultsProcessor.js b/__tests__/testResultsProcessor.cjs
similarity index 100%
rename from __tests__/testResultsProcessor.js
rename to __tests__/testResultsProcessor.cjs
diff --git a/__tests__/undock/install.test.ts b/__tests__/undock/install.test.ts
index fe604cff..3d075804 100644
--- a/__tests__/undock/install.test.ts
+++ b/__tests__/undock/install.test.ts
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-import {describe, expect, it, jest, test, afterEach} from '@jest/globals';
+import {describe, expect, it, test, afterEach} from '@jest/globals';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 import * as rimraf from 'rimraf';
-import osm = require('os');
+
+import {mockArch, mockPlatform} from '../.helpers/os';
 
 import {Install} from '../../src/undock/install';
 
@@ -80,8 +81,8 @@ describe('download', () => {
     ['linux', 's390x'],
   ])(
   'acquires undock for %s/%s', async (os, arch) => {
-    jest.spyOn(osm, 'platform').mockImplementation(() => os as NodeJS.Platform);
-    jest.spyOn(osm, 'arch').mockImplementation(() => arch);
+    mockPlatform(os as NodeJS.Platform);
+    mockArch(arch);
     const install = new Install();
     const undockBin = await install.download('latest');
     expect(fs.existsSync(undockBin)).toBe(true);
diff --git a/eslint.config.js b/eslint.config.cjs
similarity index 93%
rename from eslint.config.js
rename to eslint.config.cjs
index dfaf93e3..fe8611b0 100644
--- a/eslint.config.js
+++ b/eslint.config.cjs
@@ -62,7 +62,7 @@ module.exports = defineConfig([
       },
       parser: tsParser,
       ecmaVersion: 2023,
-      sourceType: 'commonjs'
+      sourceType: 'module'
     },
 
     rules: {
@@ -75,7 +75,7 @@ module.exports = defineConfig([
       'import/no-unresolved': [
         'error',
         {
-          ignore: ['csv-parse/sync', '@octokit/openapi-types']
+          ignore: ['\\.js$', 'csv-parse/sync', '@octokit/openapi-types', '@octokit/core', '@octokit/plugin-rest-endpoint-methods']
         }
       ],
       'jest/no-disabled-tests': 0
diff --git a/jest.config.js b/jest.config.cjs
similarity index 88%
rename from jest.config.js
rename to jest.config.cjs
index 2a4a4587..374a9f06 100644
--- a/jest.config.js
+++ b/jest.config.cjs
@@ -38,13 +38,20 @@ module.exports = {
   setupFiles: ['dotenv/config'],
   testMatch: ['**/*.test.ts'],
   transform: {
-    '^.+\\.ts$': 'ts-jest'
+    '^.+\\.ts$': [
+      'ts-jest',
+      {
+        useESM: true,
+        tsconfig: '<rootDir>/tsconfig.test.json'
+      }
+    ]
   },
   moduleNameMapper: {
-    '^csv-parse/sync': '<rootDir>/node_modules/csv-parse/dist/cjs/sync.cjs'
+    '^(\\.{1,2}/.*)\\.js$': '$1'
   },
+  extensionsToTreatAsEsm: ['.ts'],
   collectCoverageFrom: ['src/**/{!(index.ts),}.ts'],
   coveragePathIgnorePatterns: ['lib/', 'node_modules/', '__mocks__/', '__tests__/'],
-  testResultsProcessor: '<rootDir>/__tests__/testResultsProcessor.js',
+  testResultsProcessor: '<rootDir>/__tests__/testResultsProcessor.cjs',
   verbose: true
 };
diff --git a/jest.config.itg.js b/jest.config.itg.cjs
similarity index 81%
rename from jest.config.itg.js
rename to jest.config.itg.cjs
index a05e702b..87547520 100644
--- a/jest.config.itg.js
+++ b/jest.config.itg.cjs
@@ -21,11 +21,18 @@ module.exports = {
   testMatch: ['**/*.test.itg.ts'],
   testTimeout: 1800000, // 30 minutes
   transform: {
-    '^.+\\.ts$': 'ts-jest'
+    '^.+\\.ts$': [
+      'ts-jest',
+      {
+        useESM: true,
+        tsconfig: '<rootDir>/tsconfig.test.json'
+      }
+    ]
   },
   moduleNameMapper: {
-    '^csv-parse/sync': '<rootDir>/node_modules/csv-parse/dist/cjs/sync.cjs'
+    '^(\\.{1,2}/.*)\\.js$': '$1'
   },
-  testResultsProcessor: '<rootDir>/__tests__/testResultsProcessor.js',
+  extensionsToTreatAsEsm: ['.ts'],
+  testResultsProcessor: '<rootDir>/__tests__/testResultsProcessor.cjs',
   verbose: false
 };
diff --git a/package.json b/package.json
index 107ee743..bfd231f8 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "@docker/actions-toolkit",
   "version": "0.0.0+unknown",
   "description": "Toolkit for Docker (GitHub) Actions",
+  "type": "module",
   "scripts": {
     "build": "tsc",
     "lint": "yarn run prettier && yarn run eslint",
@@ -12,9 +13,9 @@
     "prettier:fix": "prettier --write \"./**/*.ts\"",
     "test": "jest",
     "test:coverage": "jest --coverage",
-    "test:itg": "jest -c jest.config.itg.js --runInBand",
-    "test:itg-list": "jest -c jest.config.itg.js --listTests",
-    "test:itg-coverage": "jest -c jest.config.itg.js --coverage --runInBand"
+    "test:itg": "jest -c jest.config.itg.cjs --runInBand",
+    "test:itg-list": "jest -c jest.config.itg.cjs --listTests",
+    "test:itg-coverage": "jest -c jest.config.itg.cjs --coverage --runInBand"
   },
   "repository": {
     "type": "git",
diff --git a/src/buildkit/buildkit.ts b/src/buildkit/buildkit.ts
index ee90ab42..dbf80aeb 100644
--- a/src/buildkit/buildkit.ts
+++ b/src/buildkit/buildkit.ts
@@ -17,12 +17,12 @@
 import * as core from '@actions/core';
 import * as semver from 'semver';
 
-import {Buildx} from '../buildx/buildx';
-import {Builder} from '../buildx/builder';
-import {Docker} from '../docker/docker';
-import {Config} from './config';
+import {Buildx} from '../buildx/buildx.js';
+import {Builder} from '../buildx/builder.js';
+import {Docker} from '../docker/docker.js';
+import {Config} from './config.js';
 
-import {BuilderInfo, NodeInfo} from '../types/buildx/builder';
+import {BuilderInfo, NodeInfo} from '../types/buildx/builder.js';
 
 export interface BuildKitOpts {
   buildx?: Buildx;
diff --git a/src/buildkit/config.ts b/src/buildkit/config.ts
index 9563b4ce..bd9fa7bb 100644
--- a/src/buildkit/config.ts
+++ b/src/buildkit/config.ts
@@ -16,7 +16,7 @@
 
 import fs from 'fs';
 
-import {Context} from '../context';
+import {Context} from '../context.js';
 
 export class Config {
   public resolveFromString(s: string): string {
diff --git a/src/buildkit/git.ts b/src/buildkit/git.ts
index 2415b59b..cb9d68d3 100644
--- a/src/buildkit/git.ts
+++ b/src/buildkit/git.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {GitRef, GitURL, GitURLFragment, URLUserInfo} from '../types/buildkit/git';
+import {GitRef, GitURL, GitURLFragment, URLUserInfo} from '../types/buildkit/git.js';
 
 export class Git {
   private static protoRegexp = new RegExp('^[a-zA-Z0-9]+://');
diff --git a/src/buildx/bake.ts b/src/buildx/bake.ts
index db0dfd05..7730f9e5 100644
--- a/src/buildx/bake.ts
+++ b/src/buildx/bake.ts
@@ -18,15 +18,15 @@ import fs from 'fs';
 import path from 'path';
 import {parse} from 'csv-parse/sync';
 
-import {Buildx} from './buildx';
-import {Context} from '../context';
-import {Exec} from '../exec';
-import {Util} from '../util';
+import {Buildx} from './buildx.js';
+import {Context} from '../context.js';
+import {Exec} from '../exec.js';
+import {Util} from '../util.js';
 
 import {ExecOptions} from '@actions/exec';
-import {AttestEntry, BakeDefinition, CacheEntry, ExportEntry, SecretEntry, SSHEntry} from '../types/buildx/bake';
-import {BuildMetadata} from '../types/buildx/build';
-import {VertexWarning} from '../types/buildkit/client';
+import {AttestEntry, BakeDefinition, CacheEntry, ExportEntry, SecretEntry, SSHEntry} from '../types/buildx/bake.js';
+import {BuildMetadata} from '../types/buildx/build.js';
+import {VertexWarning} from '../types/buildkit/client.js';
 
 export interface BakeOpts {
   buildx?: Buildx;
diff --git a/src/buildx/build.ts b/src/buildx/build.ts
index cd385e8b..5cf3e919 100644
--- a/src/buildx/build.ts
+++ b/src/buildx/build.ts
@@ -19,14 +19,14 @@ import path from 'path';
 import * as core from '@actions/core';
 import {parse} from 'csv-parse/sync';
 
-import {Buildx} from './buildx';
-import {Context} from '../context';
-import {GitHub} from '../github';
-import {Util} from '../util';
-
-import {BuildMetadata} from '../types/buildx/build';
-import {VertexWarning} from '../types/buildkit/client';
-import {ProvenancePredicate} from '../types/intoto/slsa_provenance/v0.2/provenance';
+import {Buildx} from './buildx.js';
+import {Context} from '../context.js';
+import {GitHub} from '../github.js';
+import {Util} from '../util.js';
+
+import {BuildMetadata} from '../types/buildx/build.js';
+import {VertexWarning} from '../types/buildkit/client.js';
+import {ProvenancePredicate} from '../types/intoto/slsa_provenance/v0.2/provenance.js';
 
 export interface BuildOpts {
   buildx?: Buildx;
diff --git a/src/buildx/builder.ts b/src/buildx/builder.ts
index 2e54e8e1..8f902a14 100644
--- a/src/buildx/builder.ts
+++ b/src/buildx/builder.ts
@@ -16,10 +16,10 @@
 
 import * as core from '@actions/core';
 
-import {Buildx} from './buildx';
-import {Exec} from '../exec';
+import {Buildx} from './buildx.js';
+import {Exec} from '../exec.js';
 
-import {BuilderInfo, Device, GCPolicy, NodeInfo} from '../types/buildx/builder';
+import {BuilderInfo, Device, GCPolicy, NodeInfo} from '../types/buildx/builder.js';
 
 export interface BuilderOpts {
   buildx?: Buildx;
diff --git a/src/buildx/buildx.ts b/src/buildx/buildx.ts
index ef5f41ce..2b26a1b0 100644
--- a/src/buildx/buildx.ts
+++ b/src/buildx/buildx.ts
@@ -19,16 +19,16 @@ import path from 'path';
 import * as core from '@actions/core';
 import * as semver from 'semver';
 
-import {Git} from '../buildkit/git';
-import {Docker} from '../docker/docker';
-import {GitHub} from '../github';
-import {Exec} from '../exec';
-import {Util} from '../util';
-
-import {VertexWarning} from '../types/buildkit/client';
-import {GitURL} from '../types/buildkit/git';
-import {Cert, LocalRefsOpts, LocalRefsResponse, LocalState} from '../types/buildx/buildx';
-import {GitHubAnnotation} from '../types/github';
+import {Git} from '../buildkit/git.js';
+import {Docker} from '../docker/docker.js';
+import {GitHub} from '../github.js';
+import {Exec} from '../exec.js';
+import {Util} from '../util.js';
+
+import {VertexWarning} from '../types/buildkit/client.js';
+import {GitURL} from '../types/buildkit/git.js';
+import {Cert, LocalRefsOpts, LocalRefsResponse, LocalState} from '../types/buildx/buildx.js';
+import {GitHubAnnotation} from '../types/github.js';
 
 export interface BuildxOpts {
   standalone?: boolean;
diff --git a/src/buildx/history.ts b/src/buildx/history.ts
index 02abde6d..c8067ffd 100644
--- a/src/buildx/history.ts
+++ b/src/buildx/history.ts
@@ -21,14 +21,14 @@ import path from 'path';
 import {Readable, Writable} from 'stream';
 import * as core from '@actions/core';
 
-import {Buildx} from './buildx';
-import {Context} from '../context';
-import {Docker} from '../docker/docker';
-import {Exec} from '../exec';
-import {GitHub} from '../github';
-import {Util} from '../util';
-
-import {ExportOpts, ExportResponse, InspectOpts, InspectResponse, Summaries} from '../types/buildx/history';
+import {Buildx} from './buildx.js';
+import {Context} from '../context.js';
+import {Docker} from '../docker/docker.js';
+import {Exec} from '../exec.js';
+import {GitHub} from '../github.js';
+import {Util} from '../util.js';
+
+import {ExportOpts, ExportResponse, InspectOpts, InspectResponse, Summaries} from '../types/buildx/history.js';
 
 export interface HistoryOpts {
   buildx?: Buildx;
diff --git a/src/buildx/imagetools.ts b/src/buildx/imagetools.ts
index dfaac461..ca35acd1 100644
--- a/src/buildx/imagetools.ts
+++ b/src/buildx/imagetools.ts
@@ -14,13 +14,13 @@
  * limitations under the License.
  */
 
-import {Buildx} from './buildx';
-import {Exec} from '../exec';
+import {Buildx} from './buildx.js';
+import {Exec} from '../exec.js';
 
-import {Manifest as ImageToolsManifest} from '../types/buildx/imagetools';
-import {Image} from '../types/oci/config';
-import {Descriptor, Platform} from '../types/oci/descriptor';
-import {Digest} from '../types/oci/digest';
+import {Manifest as ImageToolsManifest} from '../types/buildx/imagetools.js';
+import {Image} from '../types/oci/config.js';
+import {Descriptor, Platform} from '../types/oci/descriptor.js';
+import {Digest} from '../types/oci/digest.js';
 
 export interface ImageToolsOpts {
   buildx?: Buildx;
diff --git a/src/buildx/install.ts b/src/buildx/install.ts
index 2fc61f84..293b152b 100644
--- a/src/buildx/install.ts
+++ b/src/buildx/install.ts
@@ -22,17 +22,17 @@ import * as tc from '@actions/tool-cache';
 import * as semver from 'semver';
 import * as util from 'util';
 
-import {Buildx} from './buildx';
-import {Cache} from '../cache';
-import {Context} from '../context';
-import {Exec} from '../exec';
-import {Docker} from '../docker/docker';
-import {Git} from '../git';
-import {GitHub} from '../github';
-import {Util} from '../util';
-
-import {DownloadVersion} from '../types/buildx/buildx';
-import {GitHubRelease} from '../types/github';
+import {Buildx} from './buildx.js';
+import {Cache} from '../cache.js';
+import {Context} from '../context.js';
+import {Exec} from '../exec.js';
+import {Docker} from '../docker/docker.js';
+import {Git} from '../git.js';
+import {GitHub} from '../github.js';
+import {Util} from '../util.js';
+
+import {DownloadVersion} from '../types/buildx/buildx.js';
+import {GitHubRelease} from '../types/github.js';
 
 export interface InstallOpts {
   standalone?: boolean;
diff --git a/src/compose/compose.ts b/src/compose/compose.ts
index 5548b70f..7b3327d0 100644
--- a/src/compose/compose.ts
+++ b/src/compose/compose.ts
@@ -16,8 +16,8 @@
 
 import * as core from '@actions/core';
 
-import {Docker} from '../docker/docker';
-import {Exec} from '../exec';
+import {Docker} from '../docker/docker.js';
+import {Exec} from '../exec.js';
 
 export interface ComposeOpts {
   standalone?: boolean;
diff --git a/src/compose/install.ts b/src/compose/install.ts
index 10349821..de0456e8 100644
--- a/src/compose/install.ts
+++ b/src/compose/install.ts
@@ -22,13 +22,13 @@ import * as tc from '@actions/tool-cache';
 import * as semver from 'semver';
 import * as util from 'util';
 
-import {Cache} from '../cache';
-import {Context} from '../context';
-import {Docker} from '../docker/docker';
-import {GitHub} from '../github';
+import {Cache} from '../cache.js';
+import {Context} from '../context.js';
+import {Docker} from '../docker/docker.js';
+import {GitHub} from '../github.js';
 
-import {DownloadVersion} from '../types/compose/compose';
-import {GitHubRelease} from '../types/github';
+import {DownloadVersion} from '../types/compose/compose.js';
+import {GitHubRelease} from '../types/github.js';
 
 export interface InstallOpts {
   standalone?: boolean;
diff --git a/src/context.ts b/src/context.ts
index 502bb3e9..0e6c0409 100644
--- a/src/context.ts
+++ b/src/context.ts
@@ -20,7 +20,7 @@ import path from 'path';
 import * as tmp from 'tmp';
 import * as github from '@actions/github';
 
-import {GitHub} from './github';
+import {GitHub} from './github.js';
 
 export class Context {
   private static readonly _tmpDir = fs.mkdtempSync(path.join(Context.ensureDirExists(process.env.RUNNER_TEMP || os.tmpdir()), 'docker-actions-toolkit-'));
diff --git a/src/cosign/cosign.ts b/src/cosign/cosign.ts
index f280caf3..1b83cd05 100644
--- a/src/cosign/cosign.ts
+++ b/src/cosign/cosign.ts
@@ -17,9 +17,9 @@
 import * as core from '@actions/core';
 import {BUNDLE_V03_MEDIA_TYPE, SerializedBundle} from '@sigstore/bundle';
 
-import {Exec} from '../exec';
+import {Exec} from '../exec.js';
 import * as semver from 'semver';
-import {MEDIATYPE_EMPTY_JSON_V1} from '../types/oci/mediatype';
+import {MEDIATYPE_EMPTY_JSON_V1} from '../types/oci/mediatype.js';
 
 export interface CosignOpts {
   binPath?: string;
diff --git a/src/cosign/install.ts b/src/cosign/install.ts
index 4a512e2e..56a01525 100644
--- a/src/cosign/install.ts
+++ b/src/cosign/install.ts
@@ -25,17 +25,17 @@ import {toSignedEntity, toTrustMaterial, Verifier} from '@sigstore/verify';
 import * as semver from 'semver';
 import * as util from 'util';
 
-import {Buildx} from '../buildx/buildx';
-import {Cache} from '../cache';
-import {Context} from '../context';
-import {Exec} from '../exec';
-import {Git} from '../git';
-import {GitHub} from '../github';
-import {Util} from '../util';
-
-import {DownloadVersion} from '../types/cosign/cosign';
-import {GitHubRelease} from '../types/github';
-import {dockerfileContent} from './dockerfile';
+import {Buildx} from '../buildx/buildx.js';
+import {Cache} from '../cache.js';
+import {Context} from '../context.js';
+import {Exec} from '../exec.js';
+import {Git} from '../git.js';
+import {GitHub} from '../github.js';
+import {Util} from '../util.js';
+
+import {DownloadVersion} from '../types/cosign/cosign.js';
+import {GitHubRelease} from '../types/github.js';
+import {dockerfileContent} from './dockerfile.js';
 
 export interface DownloadOpts {
   version: string;
diff --git a/src/docker/assets.ts b/src/docker/assets.ts
index 89b7c269..abbd721f 100644
--- a/src/docker/assets.ts
+++ b/src/docker/assets.ts
@@ -15,7 +15,7 @@
  */
 
 import fs from 'fs';
-import {Context} from '../context';
+import {Context} from '../context.js';
 
 export const setupDockerWinPs1 = (): string => {
   return get('docker-setup-win.ps1', setupDockerWinPs1Data);
diff --git a/src/docker/docker.ts b/src/docker/docker.ts
index 7bb978e7..f7fac241 100644
--- a/src/docker/docker.ts
+++ b/src/docker/docker.ts
@@ -21,12 +21,12 @@ import * as core from '@actions/core';
 import {ExecOptions, ExecOutput} from '@actions/exec';
 import * as io from '@actions/io';
 
-import {Context} from '../context';
-import {Cache} from '../cache';
-import {Exec} from '../exec';
-import {Util} from '../util';
+import {Context} from '../context.js';
+import {Cache} from '../cache.js';
+import {Exec} from '../exec.js';
+import {Util} from '../util.js';
 
-import {ConfigFile, ContextInfo} from '../types/docker/docker';
+import {ConfigFile, ContextInfo} from '../types/docker/docker.js';
 
 export class Docker {
   static get configDir(): string {
diff --git a/src/docker/install.ts b/src/docker/install.ts
index a1996789..5fcdb837 100644
--- a/src/docker/install.ts
+++ b/src/docker/install.ts
@@ -25,18 +25,18 @@ import * as core from '@actions/core';
 import * as io from '@actions/io';
 import * as tc from '@actions/tool-cache';
 
-import {Context} from '../context';
-import {Docker} from './docker';
-import {Exec} from '../exec';
-import {GitHub} from '../github';
-import {Regctl} from '../regclient/regctl';
-import {Undock} from '../undock/undock';
-import {Util} from '../util';
-
-import {limaYamlData, dockerServiceLogsPs1, setupDockerWinPs1} from './assets';
-
-import {GitHubRelease} from '../types/github';
-import {Image} from '../types/oci/config';
+import {Context} from '../context.js';
+import {Docker} from './docker.js';
+import {Exec} from '../exec.js';
+import {GitHub} from '../github.js';
+import {Regctl} from '../regclient/regctl.js';
+import {Undock} from '../undock/undock.js';
+import {Util} from '../util.js';
+
+import {limaYamlData, dockerServiceLogsPs1, setupDockerWinPs1} from './assets.js';
+
+import {GitHubRelease} from '../types/github.js';
+import {Image} from '../types/oci/config.js';
 
 export interface InstallSourceImage {
   type: 'image';
diff --git a/src/dockerhub.ts b/src/dockerhub.ts
index 3bf1d59c..6bf8b437 100644
--- a/src/dockerhub.ts
+++ b/src/dockerhub.ts
@@ -18,7 +18,7 @@ import * as core from '@actions/core';
 import * as httpm from '@actions/http-client';
 import {HttpCodes} from '@actions/http-client';
 
-import {RepositoryRequest, RepositoryResponse, RepositoryTagsRequest, RepositoryTagsResponse, TokenRequest, TokenResponse, UpdateRepoDescriptionRequest} from './types/dockerhub';
+import {RepositoryRequest, RepositoryResponse, RepositoryTagsRequest, RepositoryTagsResponse, TokenRequest, TokenResponse, UpdateRepoDescriptionRequest} from './types/dockerhub.js';
 
 export interface DockerHubOpts {
   credentials: TokenRequest;
diff --git a/src/git.ts b/src/git.ts
index c43af4dc..b69f50bd 100644
--- a/src/git.ts
+++ b/src/git.ts
@@ -15,18 +15,18 @@
  */
 
 import * as core from '@actions/core';
+import * as github from '@actions/github';
 import {Octokit} from '@octokit/core';
 import {restEndpointMethods} from '@octokit/plugin-rest-endpoint-methods';
 
-import {Exec} from './exec';
-import {GitHub} from './github';
-import {Context} from '@actions/github/lib/context';
+import {Exec} from './exec.js';
+import {GitHub} from './github.js';
 
-import {Context as GitContext} from './types/git';
+export type GitContext = typeof github.context;
 
 export class Git {
   public static async context(): Promise<GitContext> {
-    const ctx = new Context();
+    const ctx = {...github.context} as GitContext;
     ctx.ref = await Git.ref();
     ctx.sha = await Git.fullCommit();
     return ctx;
diff --git a/src/github.ts b/src/github.ts
index c5a335c1..403f2543 100644
--- a/src/github.ts
+++ b/src/github.ts
@@ -27,18 +27,15 @@ import {getBackendIdsFromToken} from '@actions/artifact/lib/internal/shared/util
 import {getExpiration} from '@actions/artifact/lib/internal/upload/retention';
 import {InvalidResponseError, NetworkError} from '@actions/artifact';
 import * as core from '@actions/core';
-import {SummaryTableCell} from '@actions/core/lib/summary';
 import * as github from '@actions/github';
-import {GitHub as Octokit} from '@actions/github/lib/utils';
-import {Context} from '@actions/github/lib/context';
 import * as httpm from '@actions/http-client';
 import {TransferProgressEvent} from '@azure/core-rest-pipeline';
 import {BlobClient, BlobHTTPHeaders} from '@azure/storage-blob';
 import {jwtDecode, JwtPayload} from 'jwt-decode';
 
-import {Util} from './util';
+import {Util} from './util.js';
 
-import {BuildSummaryOpts, GitHubActionsRuntimeToken, GitHubActionsRuntimeTokenAC, GitHubContentOpts, GitHubRelease, GitHubRepo, UploadArtifactOpts, UploadArtifactResponse} from './types/github';
+import {BuildSummaryOpts, GitHubActionsRuntimeToken, GitHubActionsRuntimeTokenAC, GitHubContentOpts, GitHubRelease, GitHubRepo, SummaryTableCell, UploadArtifactOpts, UploadArtifactResponse} from './types/github.js';
 
 export interface GitHubOpts {
   token?: string;
@@ -46,7 +43,7 @@ export interface GitHubOpts {
 
 export class GitHub {
   private readonly githubToken?: string;
-  public readonly octokit: InstanceType<typeof Octokit>;
+  public readonly octokit: ReturnType<typeof github.getOctokit>;
 
   constructor(opts?: GitHubOpts) {
     this.githubToken = opts?.token || process.env.GITHUB_TOKEN;
@@ -87,7 +84,7 @@ export class GitHub {
     return <Record<string, GitHubRelease>>JSON.parse(dt);
   }
 
-  static get context(): Context {
+  static get context(): typeof github.context {
     return github.context;
   }
 
diff --git a/src/index.ts b/src/index.ts
index 9c23eacb..e58f646c 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -16,7 +16,7 @@
 
 import * as core from '@actions/core';
 
-import {Cache} from './cache';
+import {Cache} from './cache.js';
 
 const isPost = !!process.env['STATE_isPost'];
 if (!isPost) {
diff --git a/src/oci/oci.ts b/src/oci/oci.ts
index da888b48..c1dff3a2 100644
--- a/src/oci/oci.ts
+++ b/src/oci/oci.ts
@@ -20,13 +20,13 @@ import * as path from 'path';
 import {Readable} from 'stream';
 import * as tar from 'tar-stream';
 
-import {Archive, LoadArchiveOpts} from '../types/oci/oci';
-import {Index} from '../types/oci';
-import {Platform} from '../types/oci/descriptor';
-import {Manifest} from '../types/oci/manifest';
-import {Image} from '../types/oci/config';
-import {IMAGE_BLOBS_DIR_V1, IMAGE_INDEX_FILE_V1, IMAGE_LAYOUT_FILE_V1, ImageLayout} from '../types/oci/layout';
-import {MEDIATYPE_IMAGE_INDEX_V1, MEDIATYPE_IMAGE_MANIFEST_V1} from '../types/oci/mediatype';
+import {Archive, LoadArchiveOpts} from '../types/oci/oci.js';
+import {Index} from '../types/oci/index.js';
+import {Platform} from '../types/oci/descriptor.js';
+import {Manifest} from '../types/oci/manifest.js';
+import {Image} from '../types/oci/config.js';
+import {IMAGE_BLOBS_DIR_V1, IMAGE_INDEX_FILE_V1, IMAGE_LAYOUT_FILE_V1, ImageLayout} from '../types/oci/layout.js';
+import {MEDIATYPE_IMAGE_INDEX_V1, MEDIATYPE_IMAGE_MANIFEST_V1} from '../types/oci/mediatype.js';
 
 export class OCI {
   public static defaultPlatform(): Platform {
diff --git a/src/regclient/install.ts b/src/regclient/install.ts
index 5c14aaf3..9edb407b 100644
--- a/src/regclient/install.ts
+++ b/src/regclient/install.ts
@@ -22,12 +22,12 @@ import * as tc from '@actions/tool-cache';
 import * as semver from 'semver';
 import * as util from 'util';
 
-import {Cache} from '../cache';
-import {Context} from '../context';
-import {GitHub} from '../github';
+import {Cache} from '../cache.js';
+import {Context} from '../context.js';
+import {GitHub} from '../github.js';
 
-import {GitHubRelease} from '../types/github';
-import {DownloadVersion} from '../types/regclient/regclient';
+import {GitHubRelease} from '../types/github.js';
+import {DownloadVersion} from '../types/regclient/regclient.js';
 
 export interface InstallOpts {
   githubToken?: string;
diff --git a/src/regclient/regctl.ts b/src/regclient/regctl.ts
index b784d9da..868cab8f 100644
--- a/src/regclient/regctl.ts
+++ b/src/regclient/regctl.ts
@@ -17,9 +17,9 @@
 import * as core from '@actions/core';
 import * as semver from 'semver';
 
-import {Exec} from '../exec';
+import {Exec} from '../exec.js';
 
-import {Manifest} from '../types/oci/manifest';
+import {Manifest} from '../types/oci/manifest.js';
 
 export interface RegctlOpts {
   binPath?: string;
diff --git a/src/sigstore/sigstore.ts b/src/sigstore/sigstore.ts
index 8b8ad0e3..6fa8966a 100644
--- a/src/sigstore/sigstore.ts
+++ b/src/sigstore/sigstore.ts
@@ -22,13 +22,13 @@ import * as core from '@actions/core';
 import {bundleFromJSON, bundleToJSON} from '@sigstore/bundle';
 import {Artifact, Bundle, CIContextProvider, DSSEBundleBuilder, FulcioSigner, RekorWitness, TSAWitness, Witness} from '@sigstore/sign';
 
-import {Context} from '../context';
-import {Cosign} from '../cosign/cosign';
-import {Exec} from '../exec';
-import {GitHub} from '../github';
-import {ImageTools} from '../buildx/imagetools';
+import {Context} from '../context.js';
+import {Cosign} from '../cosign/cosign.js';
+import {Exec} from '../exec.js';
+import {GitHub} from '../github.js';
+import {ImageTools} from '../buildx/imagetools.js';
 
-import {MEDIATYPE_PAYLOAD as INTOTO_MEDIATYPE_PAYLOAD, Subject} from '../types/intoto/intoto';
+import {MEDIATYPE_PAYLOAD as INTOTO_MEDIATYPE_PAYLOAD, Subject} from '../types/intoto/intoto.js';
 import {
   Endpoints,
   FULCIO_URL,
@@ -44,7 +44,7 @@ import {
   VerifySignedArtifactsResult,
   VerifySignedManifestsOpts,
   VerifySignedManifestsResult
-} from '../types/sigstore/sigstore';
+} from '../types/sigstore/sigstore.js';
 
 export interface SigstoreOpts {
   cosign?: Cosign;
diff --git a/src/toolkit.ts b/src/toolkit.ts
index 1994276d..1563ce0b 100644
--- a/src/toolkit.ts
+++ b/src/toolkit.ts
@@ -14,22 +14,22 @@
  * limitations under the License.
  */
 
-import {GitHub} from './github';
-import {Buildx} from './buildx/buildx';
-import {Build as BuildxBuild} from './buildx/build';
-import {Bake as BuildxBake} from './buildx/bake';
-import {Install as BuildxInstall} from './buildx/install';
-import {Builder} from './buildx/builder';
-import {BuildKit} from './buildkit/buildkit';
-import {Compose} from './compose/compose';
-import {Install as ComposeInstall} from './compose/install';
-import {Cosign} from './cosign/cosign';
-import {Install as CosignInstall} from './cosign/install';
-import {Regctl} from './regclient/regctl';
-import {Install as RegctlInstall} from './regclient/install';
-import {Undock} from './undock/undock';
-import {Install as UndockInstall} from './undock/install';
-import {Sigstore} from './sigstore/sigstore';
+import {GitHub} from './github.js';
+import {Buildx} from './buildx/buildx.js';
+import {Build as BuildxBuild} from './buildx/build.js';
+import {Bake as BuildxBake} from './buildx/bake.js';
+import {Install as BuildxInstall} from './buildx/install.js';
+import {Builder} from './buildx/builder.js';
+import {BuildKit} from './buildkit/buildkit.js';
+import {Compose} from './compose/compose.js';
+import {Install as ComposeInstall} from './compose/install.js';
+import {Cosign} from './cosign/cosign.js';
+import {Install as CosignInstall} from './cosign/install.js';
+import {Regctl} from './regclient/regctl.js';
+import {Install as RegctlInstall} from './regclient/install.js';
+import {Undock} from './undock/undock.js';
+import {Install as UndockInstall} from './undock/install.js';
+import {Sigstore} from './sigstore/sigstore.js';
 
 export interface ToolkitOpts {
   /**
diff --git a/src/types/buildkit/client.ts b/src/types/buildkit/client.ts
index 0a913426..a14f4457 100644
--- a/src/types/buildkit/client.ts
+++ b/src/types/buildkit/client.ts
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import {Digest} from '../oci/digest';
-import {ProgressGroup, Range, SourceInfo} from './ops';
+import {Digest} from '../oci/digest.js';
+import {ProgressGroup, Range, SourceInfo} from './ops.js';
 
 // https://github.com/moby/buildkit/blob/v0.14.0/client/graph.go#L10-L19
 export interface Vertex {
diff --git a/src/types/buildkit/control.ts b/src/types/buildkit/control.ts
index 3d3f157a..0d7f9756 100644
--- a/src/types/buildkit/control.ts
+++ b/src/types/buildkit/control.ts
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-import {Descriptor} from '../oci/descriptor';
-import {Digest} from '../oci/digest';
-import {ProgressGroup, Range, SourceInfo} from './ops';
-import {RpcStatus} from './rpc';
+import {Descriptor} from '../oci/descriptor.js';
+import {Digest} from '../oci/digest.js';
+import {ProgressGroup, Range, SourceInfo} from './ops.js';
+import {RpcStatus} from './rpc.js';
 
 // https://github.com/moby/buildkit/blob/v0.14.0/api/services/control/control.pb.go#L1504-L1525
 export interface BuildHistoryRecord {
diff --git a/src/types/buildx/buildx.ts b/src/types/buildx/buildx.ts
index 10ede92f..0047a190 100644
--- a/src/types/buildx/buildx.ts
+++ b/src/types/buildx/buildx.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {GitHubContentOpts} from '../github';
+import {GitHubContentOpts} from '../github.js';
 
 export interface Cert {
   cacert?: string;
diff --git a/src/types/buildx/imagetools.ts b/src/types/buildx/imagetools.ts
index 4594c7fb..ce2007ff 100644
--- a/src/types/buildx/imagetools.ts
+++ b/src/types/buildx/imagetools.ts
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-import {Versioned} from '../oci/versioned';
-import {Descriptor} from '../oci/descriptor';
-import {Digest} from '../oci/digest';
+import {Versioned} from '../oci/versioned.js';
+import {Descriptor} from '../oci/descriptor.js';
+import {Digest} from '../oci/digest.js';
 
 // https://github.com/docker/buildx/blob/62857022a08552bee5cad0c3044a9a3b185f0b32/util/imagetools/printers.go#L109-L123
 export interface Manifest extends Versioned {
diff --git a/src/types/compose/compose.ts b/src/types/compose/compose.ts
index 4e69ea92..8bb536d4 100644
--- a/src/types/compose/compose.ts
+++ b/src/types/compose/compose.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {GitHubContentOpts} from '../github';
+import {GitHubContentOpts} from '../github.js';
 
 export interface DownloadVersion {
   key: string;
diff --git a/src/types/cosign/cosign.ts b/src/types/cosign/cosign.ts
index 4aca14b8..cda1036b 100644
--- a/src/types/cosign/cosign.ts
+++ b/src/types/cosign/cosign.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {GitHubContentOpts} from '../github';
+import {GitHubContentOpts} from '../github.js';
 
 export interface DownloadVersion {
   version: string;
diff --git a/src/types/github.ts b/src/types/github.ts
index 8fc4bbea..af184ef6 100644
--- a/src/types/github.ts
+++ b/src/types/github.ts
@@ -14,12 +14,16 @@
  * limitations under the License.
  */
 
+import * as core from '@actions/core';
 import {AnnotationProperties} from '@actions/core';
 import {components as OctoOpenApiTypes} from '@octokit/openapi-types';
 import {JwtPayload} from 'jwt-decode';
 
-import {BakeDefinition} from './buildx/bake';
-import {ExportResponse} from './buildx/history';
+import {BakeDefinition} from './buildx/bake.js';
+import {ExportResponse} from './buildx/history.js';
+
+export type SummaryTableRow = Parameters<typeof core.summary.addTable>[0][number];
+export type SummaryTableCell = Exclude<SummaryTableRow[number], string>;
 
 export interface GitHubRelease {
   id: number;
diff --git a/src/types/oci/config.ts b/src/types/oci/config.ts
index b9f0d1ca..eec05028 100644
--- a/src/types/oci/config.ts
+++ b/src/types/oci/config.ts
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import {Digest} from './digest';
-import {Platform} from './descriptor';
+import {Digest} from './digest.js';
+import {Platform} from './descriptor.js';
 
 export interface ImageConfig {
   User?: string;
diff --git a/src/types/oci/descriptor.ts b/src/types/oci/descriptor.ts
index e2de5f85..65b67965 100644
--- a/src/types/oci/descriptor.ts
+++ b/src/types/oci/descriptor.ts
@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-import {Digest} from './digest';
+import {Digest} from './digest.js';
 
-import {MEDIATYPE_EMPTY_JSON_V1} from './mediatype';
+import {MEDIATYPE_EMPTY_JSON_V1} from './mediatype.js';
 
 export interface Descriptor {
   mediaType: string;
diff --git a/src/types/oci/index.ts b/src/types/oci/index.ts
index 480aab5f..2dcf0545 100644
--- a/src/types/oci/index.ts
+++ b/src/types/oci/index.ts
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import {Versioned} from './versioned';
-import {Descriptor} from './descriptor';
+import {Versioned} from './versioned.js';
+import {Descriptor} from './descriptor.js';
 
 export interface Index extends Versioned {
   mediaType?: string;
diff --git a/src/types/oci/manifest.ts b/src/types/oci/manifest.ts
index 14e28a69..d7741622 100644
--- a/src/types/oci/manifest.ts
+++ b/src/types/oci/manifest.ts
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-import {Descriptor} from './descriptor';
-import {Versioned} from './versioned';
+import {Descriptor} from './descriptor.js';
+import {Versioned} from './versioned.js';
 
 export interface Manifest extends Versioned {
   mediaType?: string;
diff --git a/src/types/oci/oci.ts b/src/types/oci/oci.ts
index 0b36a71b..e0483e29 100644
--- a/src/types/oci/oci.ts
+++ b/src/types/oci/oci.ts
@@ -14,10 +14,10 @@
  * limitations under the License.
  */
 
-import {Index} from './index';
-import {ImageLayout} from './layout';
-import {Manifest} from './manifest';
-import {Image} from './config';
+import {Index} from './index.js';
+import {ImageLayout} from './layout.js';
+import {Manifest} from './manifest.js';
+import {Image} from './config.js';
 
 export interface LoadArchiveOpts {
   file: string;
diff --git a/src/types/regclient/regclient.ts b/src/types/regclient/regclient.ts
index 4aca14b8..cda1036b 100644
--- a/src/types/regclient/regclient.ts
+++ b/src/types/regclient/regclient.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {GitHubContentOpts} from '../github';
+import {GitHubContentOpts} from '../github.js';
 
 export interface DownloadVersion {
   version: string;
diff --git a/src/types/sigstore/sigstore.ts b/src/types/sigstore/sigstore.ts
index b08e1ffe..d6a2d70c 100644
--- a/src/types/sigstore/sigstore.ts
+++ b/src/types/sigstore/sigstore.ts
@@ -16,8 +16,8 @@
 
 import type {SerializedBundle} from '@sigstore/bundle';
 
-import {Subject} from '../intoto/intoto';
-import {Platform} from '../oci/descriptor';
+import {Subject} from '../intoto/intoto.js';
+import {Platform} from '../oci/descriptor.js';
 
 export const FULCIO_URL = 'https://fulcio.sigstore.dev';
 export const REKOR_URL = 'https://rekor.sigstore.dev';
diff --git a/src/types/undock/undock.ts b/src/types/undock/undock.ts
index 21374ca9..745ca280 100644
--- a/src/types/undock/undock.ts
+++ b/src/types/undock/undock.ts
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import {GitHubContentOpts} from '../github';
+import {GitHubContentOpts} from '../github.js';
 
 export interface DownloadVersion {
   version: string;
diff --git a/src/undock/install.ts b/src/undock/install.ts
index 2b190036..887a254b 100644
--- a/src/undock/install.ts
+++ b/src/undock/install.ts
@@ -22,12 +22,12 @@ import * as tc from '@actions/tool-cache';
 import * as semver from 'semver';
 import * as util from 'util';
 
-import {Cache} from '../cache';
-import {Context} from '../context';
-import {GitHub} from '../github';
+import {Cache} from '../cache.js';
+import {Context} from '../context.js';
+import {GitHub} from '../github.js';
 
-import {GitHubRelease} from '../types/github';
-import {DownloadVersion} from '../types/undock/undock';
+import {GitHubRelease} from '../types/github.js';
+import {DownloadVersion} from '../types/undock/undock.js';
 
 export interface InstallOpts {
   githubToken?: string;
diff --git a/src/undock/undock.ts b/src/undock/undock.ts
index f75b320b..a93017b3 100644
--- a/src/undock/undock.ts
+++ b/src/undock/undock.ts
@@ -17,7 +17,7 @@
 import * as core from '@actions/core';
 import * as semver from 'semver';
 
-import {Exec} from '../exec';
+import {Exec} from '../exec.js';
 
 export interface UndockOpts {
   binPath?: string;
diff --git a/tsconfig.json b/tsconfig.json
index 9dd4a983..88dabea4 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,8 +1,8 @@
 {
   "compilerOptions": {
+    "module": "es2020",
+    "moduleResolution": "bundler",
     "esModuleInterop": true,
-    "target": "es6",
-    "module": "node16",
     "isolatedModules": true,
     "strict": true,
     "declaration": true,
@@ -14,6 +14,7 @@
     "noImplicitAny": false,
     "resolveJsonModule": true,
     "useUnknownInCatchVariables": false,
+    "skipLibCheck": true,
   },
   "exclude": [
     "./__mocks__/**/*",
diff --git a/tsconfig.test.json b/tsconfig.test.json
new file mode 100644
index 00000000..d78b1e5f
--- /dev/null
+++ b/tsconfig.test.json
@@ -0,0 +1,15 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "rootDir": ".",
+    "noEmit": true
+  },
+  "include": [
+    "src/**/*.ts",
+    "__tests__/**/*.ts"
+  ],
+  "exclude": [
+    "lib",
+    "node_modules"
+  ]
+}