diff --git a/package.json b/package.json
index 41e74ae..ae5a829 100644
--- a/package.json
+++ b/package.json
@@ -3,9 +3,9 @@
   "version": "2.3.1",
   "description": "A React Compiler violation tracker to help migrations and prevent regressions",
   "type": "module",
-  "main": "dist/index.mjs",
+  "main": "dist/index.js",
   "bin": {
-    "react-compiler-tracker": "dist/index.mjs"
+    "react-compiler-tracker": "dist/index.js"
   },
   "scripts": {
     "check": "run-p check:* -c -l",
@@ -44,7 +44,7 @@
     "CHANGELOG.md"
   ],
   "lint-staged": {
-    "*.{js,ts,mjs,mts,json,md}": "biome check --write --no-errors-on-unmatched"
+    "*.{js,ts,json,md}": "biome check --write --no-errors-on-unmatched"
   },
   "devDependencies": {
     "rimraf": "6.1.2",
diff --git a/src/args.test.mts b/src/args.test.ts
similarity index 98%
rename from src/args.test.mts
rename to src/args.test.ts
index 3dabf53..49f8030 100644
--- a/src/args.test.mts
+++ b/src/args.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { parseArgs } from './args.mjs'
+import { parseArgs } from './args.js'
 
 describe('parseArgs', () => {
     it('parses --check-files with files', () => {
diff --git a/src/args.mts b/src/args.ts
similarity index 100%
rename from src/args.mts
rename to src/args.ts
diff --git a/src/babel.mts b/src/babel.ts
similarity index 100%
rename from src/babel.mts
rename to src/babel.ts
diff --git a/src/config.test.mts b/src/config.test.ts
similarity index 97%
rename from src/config.test.mts
rename to src/config.test.ts
index abb091d..e6a1324 100644
--- a/src/config.test.mts
+++ b/src/config.test.ts
@@ -1,6 +1,6 @@
 import { existsSync, readFileSync } from 'node:fs'
 import { afterEach, describe, expect, it, vi } from 'vitest'
-import { DEFAULT_CONFIG, loadConfig } from './config.mjs'
+import { DEFAULT_CONFIG, loadConfig } from './config.js'
 
 vi.mock('node:fs', () => ({
     existsSync: vi.fn(),
diff --git a/src/config.mts b/src/config.ts
similarity index 100%
rename from src/config.mts
rename to src/config.ts
diff --git a/src/index.integration.test.mts b/src/index.integration.test.ts
similarity index 99%
rename from src/index.integration.test.mts
rename to src/index.integration.test.ts
index 72695ae..4aad977 100644
--- a/src/index.integration.test.mts
+++ b/src/index.integration.test.ts
@@ -10,7 +10,7 @@ const recordsPath = join(fixtureDir, '.react-compiler.rec.json')
 const configPath = join(fixtureDir, '.react-compiler-tracker.config.json')
 
 function runCLI(args: string[] = [], cwd = fixtureDir): string {
-    const cliPath = join(__dirname, 'index.mts')
+    const cliPath = join(__dirname, 'index.ts')
     try {
         return execSync(`npx tsx ${cliPath} ${args.join(' ')} 2>&1`, {
             cwd,
diff --git a/src/index.mts b/src/index.ts
similarity index 97%
rename from src/index.mts
rename to src/index.ts
index d128cb6..f748423 100644
--- a/src/index.mts
+++ b/src/index.ts
@@ -2,13 +2,13 @@
 
 import { join, relative } from 'node:path'
 import type { Logger as ReactCompilerLogger } from 'babel-plugin-react-compiler'
-import { parseArgs } from './args.mjs'
-import * as babel from './babel.mjs'
-import { loadConfig } from './config.mjs'
-import type { FileErrors } from './records-file.mjs'
-import * as recordsFile from './records-file.mjs'
-import * as sourceFiles from './source-files.mjs'
-import { pluralize } from './utils.mjs'
+import { parseArgs } from './args.js'
+import * as babel from './babel.js'
+import { loadConfig } from './config.js'
+import type { FileErrors } from './records-file.js'
+import * as recordsFile from './records-file.js'
+import * as sourceFiles from './source-files.js'
+import { pluralize } from './utils.js'
 
 const compilerErrors: Map<string, FileErrors> = new Map()
 
diff --git a/src/react-compiler.mts b/src/react-compiler.ts
similarity index 100%
rename from src/react-compiler.mts
rename to src/react-compiler.ts
diff --git a/src/records-file.test.mts b/src/records-file.test.ts
similarity index 98%
rename from src/records-file.test.mts
rename to src/records-file.test.ts
index 6b6ef36..166c46e 100644
--- a/src/records-file.test.mts
+++ b/src/records-file.test.ts
@@ -1,5 +1,5 @@
 import { afterEach, describe, expect, it, vi } from 'vitest'
-import { getErrorChanges, load, save } from './records-file.mjs'
+import { getErrorChanges, load, save } from './records-file.js'
 
 vi.mock('node:fs', () => ({
     existsSync: vi.fn(),
@@ -7,7 +7,7 @@ vi.mock('node:fs', () => ({
     writeFileSync: vi.fn(),
 }))
 
-vi.mock('./react-compiler.mjs', () => ({
+vi.mock('./react-compiler.js', () => ({
     getVersion: vi.fn(() => '1.0.0'),
 }))
 
diff --git a/src/records-file.mts b/src/records-file.ts
similarity index 98%
rename from src/records-file.mts
rename to src/records-file.ts
index b3f846e..f631a5d 100644
--- a/src/records-file.mts
+++ b/src/records-file.ts
@@ -3,7 +3,7 @@
 import { execSync } from 'node:child_process'
 import { existsSync, readFileSync, writeFileSync } from 'node:fs'
 
-import * as reactCompiler from './react-compiler.mjs'
+import * as reactCompiler from './react-compiler.js'
 
 const RECORD_VERSION = 1
 
diff --git a/src/source-files.test.mts b/src/source-files.test.ts
similarity index 99%
rename from src/source-files.test.mts
rename to src/source-files.test.ts
index 9809a72..433a01a 100644
--- a/src/source-files.test.mts
+++ b/src/source-files.test.ts
@@ -8,7 +8,7 @@ import {
     normalizeFilePaths,
     partitionByExistence,
     validateFilesExist,
-} from './source-files.mjs'
+} from './source-files.js'
 
 vi.mock('node:child_process', () => ({
     execSync: vi.fn(),
diff --git a/src/source-files.mts b/src/source-files.ts
similarity index 100%
rename from src/source-files.mts
rename to src/source-files.ts
diff --git a/src/utils.mts b/src/utils.ts
similarity index 100%
rename from src/utils.mts
rename to src/utils.ts
diff --git a/vitest.config.ts b/vitest.config.ts
index 8f8bfa0..cfb7a77 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -2,7 +2,7 @@ import { defineConfig } from 'vitest/config'
 
 export default defineConfig({
     test: {
-        include: ['src/**/*.test.{ts,mts}'],
+        include: ['src/**/*.test.ts'],
     },
     server: {
         watch: {