diff --git a/.github/workflows/test-and-build.yml b/.github/workflows/test-and-build.yml
index b26c509..f6863b6 100644
--- a/.github/workflows/test-and-build.yml
+++ b/.github/workflows/test-and-build.yml
@@ -53,6 +53,9 @@ jobs:
     - name: Build
       run: pnpm run build
 
+    - name: Install Playwright browsers
+      run: pnpm run playwright:install
+
     - name: Test
       run: pnpm run test:all
 
diff --git a/.gitignore b/.gitignore
index 7e5e851..fd03684 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,3 +14,6 @@ toml-patch.code-workspace
 *.cpuprofile
 benchmark-*.md
 
+
+test-results/
+playwright-report/
diff --git a/browser-tests/smoke.spec.ts b/browser-tests/smoke.spec.ts
new file mode 100644
index 0000000..7829f88
--- /dev/null
+++ b/browser-tests/smoke.spec.ts
@@ -0,0 +1,42 @@
+import { test, expect } from '@playwright/test';
+import { readFileSync } from 'fs';
+import { join } from 'path';
+
+const bundle = readFileSync(join(process.cwd(), 'dist/toml-patch.js'), 'utf-8');
+
+// Load the bundle into the page via a blob URL so it runs in a real browser
+// module context — no Node.js APIs available.
+async function loadTOML(page: import('@playwright/test').Page) {
+  await page.goto('about:blank');
+  await page.evaluate(async (src: string) => {
+    const blob = new Blob([src], { type: 'application/javascript' });
+    const url = URL.createObjectURL(blob);
+    (window as any).__TOML__ = await import(url);
+    URL.revokeObjectURL(url);
+  }, bundle);
+}
+
+test.beforeEach(async ({ page }) => {
+  await loadTOML(page);
+});
+
+test('parse should work in real browser', async ({ page }) => {
+  const result = await page.evaluate(() =>
+    (window as any).__TOML__.parse('key = "hello"')
+  );
+  expect(result).toEqual({ key: 'hello' });
+});
+
+test('stringify should work in real browser', async ({ page }) => {
+  const result = await page.evaluate(() =>
+    (window as any).__TOML__.stringify({ key: 'hello' })
+  );
+  expect(result).toBe('key = "hello"\n');
+});
+
+test('patch should work in real browser', async ({ page }) => {
+  const result = await page.evaluate(() =>
+    (window as any).__TOML__.patch('key = "hello"\n', { key: 'world' })
+  );
+  expect(result).toBe('key = "world"\n');
+});
diff --git a/jest.config.json b/jest.config.json
index 2122c45..3b4b9bf 100644
--- a/jest.config.json
+++ b/jest.config.json
@@ -2,6 +2,7 @@
   "testEnvironment": "node",
   "preset": "ts-jest",
   "testRegex": "/__tests__/(?!__js__).*\\.[jt]sx?$",
+  "testPathIgnorePatterns": ["<rootDir>/worktrees/"],
   "snapshotFormat": {
     "escapeString": true,
     "printBasicPrototype": true
diff --git a/jest.config.mjs b/jest.config.mjs
index 2f2e51d..0322355 100644
--- a/jest.config.mjs
+++ b/jest.config.mjs
@@ -4,6 +4,7 @@
 export default {
   testEnvironment: 'node',
   testRegex: '/__tests__/.*\\.mjs$',
+  testPathIgnorePatterns: ['<rootDir>/worktrees/'],
   transform: {},
   moduleNameMapper: {
     '^(\\.{1,2}/.*)\\.js$': '$1',
diff --git a/package.json b/package.json
index 563869f..202b59194 100644
--- a/package.json
+++ b/package.json
@@ -38,7 +38,9 @@
     "dev": "pnpm run typecheck && pnpm run build && npm-run-all2 --parallel test:all specs",
     "test": "jest --config jest.config.json",
     "test:js": "node --experimental-vm-modules node_modules/jest/bin/jest.js --config jest.config.mjs",
-    "test:all": "pnpm run test && pnpm run test:js",
+    "test:playwright": "playwright test",
+    "playwright:install": "playwright install --with-deps chromium",
+    "test:all": "pnpm run test && pnpm run test:js && pnpm run test:playwright",
     "typecheck": "tsc",
     "specs": "jest --config specs.config.cjs",
     "benchmark": "npm-run-all2 bench:*",
@@ -53,6 +55,7 @@
   },
   "devDependencies": {
     "@decimalturn/toml-patch": "npm:@decimalturn/toml-patch@1.0.7",
+    "@playwright/test": "^1.59.1",
     "@rollup/plugin-terser": "^1.0.0",
     "@rollup/plugin-typescript": "^12.1.2",
     "@types/dedent": "^0.7.2",
diff --git a/playwright.config.ts b/playwright.config.ts
new file mode 100644
index 0000000..7fe1285
--- /dev/null
+++ b/playwright.config.ts
@@ -0,0 +1,8 @@
+import { defineConfig } from '@playwright/test';
+
+export default defineConfig({
+  testDir: './browser-tests',
+  projects: [
+    { name: 'chromium', use: { browserName: 'chromium' } },
+  ],
+});
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 7c87e88..52d0acd 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -18,6 +18,9 @@ importers:
       '@decimalturn/toml-patch':
         specifier: npm:@decimalturn/toml-patch@1.0.7
         version: 1.0.7
+      '@playwright/test':
+        specifier: ^1.59.1
+        version: 1.59.1
       '@rollup/plugin-terser':
         specifier: ^1.0.0
         version: 1.0.0(rollup@4.60.1)
@@ -555,6 +558,11 @@ packages:
     resolution: {integrity: sha512-QNqXyfVS2wm9hweSYD2O7F0G06uurj9kZ96TRQE5Y9hU7+tgdZwIkbAKc5Ocy1HxEY2kuDQa6cQ1WRs/O5LFKA==}
     engines: {node: ^12.20.0 || ^14.18.0 || >=16.0.0}
 
+  '@playwright/test@1.59.1':
+    resolution: {integrity: sha512-PG6q63nQg5c9rIi4/Z5lR5IVF7yU5MqmKaPOe0HSc0O2cX1fPi96sUQu5j7eo4gKCkB2AnNGoWt7y4/Xx3Kcqg==}
+    engines: {node: '>=18'}
+    hasBin: true
+
   '@rollup/plugin-terser@1.0.0':
     resolution: {integrity: sha512-FnCxhTBx6bMOYQrar6C8h3scPt8/JwIzw3+AJ2K++6guogH5fYaIFia+zZuhqv0eo1RN7W1Pz630SyvLbDjhtQ==}
     engines: {node: '>=20.0.0'}
@@ -1260,6 +1268,11 @@ packages:
   fs.realpath@1.0.0:
     resolution: {integrity: sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==}
 
+  fsevents@2.3.2:
+    resolution: {integrity: sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==}
+    engines: {node: ^8.16.0 || ^10.6.0 || >=11.0.0}
+    os: [darwin]
+
   fsevents@2.3.3:
     resolution: {integrity: sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw==}
     engines: {node: ^8.16.0 || ^10.6.0 || >=11.0.0}
@@ -1935,6 +1948,16 @@ packages:
   platform@1.3.6:
     resolution: {integrity: sha512-fnWVljUchTro6RiCFvCXBbNhJc2NijN7oIQxbwsyL0buWJPG85v81ehlHI9fXrJsMNgTofEoWIQeClKpgxFLrg==}
 
+  playwright-core@1.59.1:
+    resolution: {integrity: sha512-HBV/RJg81z5BiiZ9yPzIiClYV/QMsDCKUyogwH9p3MCP6IYjUFu/MActgYAvK0oWyV9NlwM3GLBjADyWgydVyg==}
+    engines: {node: '>=18'}
+    hasBin: true
+
+  playwright@1.59.1:
+    resolution: {integrity: sha512-C8oWjPR3F81yljW9o5OxcWzfh6avkVwDD2VYdwIGqTkl+OGFISgypqzfu7dOe4QNLL2aqcWBmI3PMtLIK233lw==}
+    engines: {node: '>=18'}
+    hasBin: true
+
   pretty-format@30.3.0:
     resolution: {integrity: sha512-oG4T3wCbfeuvljnyAzhBvpN45E8iOTXCU/TD3zXW80HA3dQ4ahdqMkWGiPWZvjpQwlbyHrPTWUAqUzGzv4l1JQ==}
     engines: {node: ^18.14.0 || ^20.0.0 || ^22.0.0 || >=24.0.0}
@@ -2921,6 +2944,10 @@ snapshots:
 
   '@pkgr/core@0.2.9': {}
 
+  '@playwright/test@1.59.1':
+    dependencies:
+      playwright: 1.59.1
+
   '@rollup/plugin-terser@1.0.0(rollup@4.60.1)':
     dependencies:
       serialize-javascript: 7.0.5
@@ -3533,6 +3560,9 @@ snapshots:
 
   fs.realpath@1.0.0: {}
 
+  fsevents@2.3.2:
+    optional: true
+
   fsevents@2.3.3:
     optional: true
 
@@ -4443,6 +4473,14 @@ snapshots:
 
   platform@1.3.6: {}
 
+  playwright-core@1.59.1: {}
+
+  playwright@1.59.1:
+    dependencies:
+      playwright-core: 1.59.1
+    optionalDependencies:
+      fsevents: 2.3.2
+
   pretty-format@30.3.0:
     dependencies:
       '@jest/schemas': 30.0.5
diff --git a/tsconfig.json b/tsconfig.json
index 4e870e2..c7f1c55 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -9,6 +9,6 @@
     "noEmit": true,
     "skipLibCheck": true
   },
-  "include": ["src/**/*"],
+  "include": ["*.ts", "src/**/*"],
   "exclude": ["node_modules"]
 }
\ No newline at end of file