diff --git a/docs/guide/essentials/extension-apis.md b/docs/guide/essentials/extension-apis.md
index 898857e0..5d0187b9 100644
--- a/docs/guide/essentials/extension-apis.md
+++ b/docs/guide/essentials/extension-apis.md
@@ -4,61 +4,41 @@
 
 Different browsers provide different global variables for accessing the extension APIs (chrome provides `chrome`, firefox provides `browser`, etc).
 
-WXT simplifies this - always use `browser`:
+WXT merges these two into a unified API accessed through the `browser` variable.
 
 ```ts
+import { browser } from 'wxt/browser';
+
 browser.action.onClicked.addListener(() => {
   // ...
 });
 ```
 
-Other than that, refer to Chrome and Mozilla's documentation for how to use specific APIs. Everything a normal extension can do, WXT can do as well, just via `browser` instead of `chrome`.
+:::tip
+With auto-imports enabled, you don't even need to import this variable from `wxt/browser`!
+:::
 
-## Webextension Polyfill
-
-> Since `v0.1.0`
-
-By default, WXT uses the [`webextension-polyfill` by Mozilla](https://www.npmjs.com/package/webextension-polyfill) to make the extension API consistent between browsers.
-
-To access types, you should import the relevant namespace from `wxt/browser`:
-
-```ts
-import { Runtime } from 'wxt/browser';
-
-function handleMessage(message: any, sender: Runtime.Sender) {
-  // ...
-}
-```
-
-### Disabling the polyfill
-
-> Since `v0.19.0`
-
-After the release of MV3 and Chrome's official deprecation of MV2 in June 2024, the polyfill isn't really doing anything useful anymore.
-
-You can disable it with a single line:
-
-```ts [wxt.config.ts]
-export default defineConfig({
-  extensionApi: 'chrome',
-});
-```
-
-This will change `wxt/browser` to simply export the `browser` or `chrome` globals based on browser at runtime:
+The `browser` variable WXT provides is a simple export of the `browser` or `chrome` globals provided by the browser at runtime:
 
 <<< @/../packages/browser/src/index.mjs#snippet
 
-Accessing types is a little different with the polyfill disabled. They do not need to be imported; they're available on the `browser` object itself:
+This means you can use the promise-style API for both MV2 and MV3, and it will work across all browsers (Chromium, Firefox, Safari, etc).
+
+## Accessing Types
+
+All types can be accessed via WXT's `Browser` namespace:
 
 ```ts
-function handleMessage(message: any, sender: browser.runtime.Sender) {
+import { Browser } from 'wxt/browser';
+
+function handleMessage(message: any, sender: Browser.runtime.MessageSender) {
   // ...
 }
 ```
 
 ## Feature Detection
 
-Depending on the manifest version and browser, some APIs are not available at runtime. If an API is not available, it will be `undefined`.
+Depending on the manifest version, browser, and permissions, some APIs are not available at runtime. If an API is not available, it will be `undefined`.
 
 :::warning
 Types will not help you here. The types WXT provides for `browser` assume all APIs exist. You are responsible for knowing whether an API is available or not.
diff --git a/packages/browser/src/__tests__/index.test.ts b/packages/browser/src/__tests__/index.test.ts
index 1fb8330c..07b40f51 100644
--- a/packages/browser/src/__tests__/index.test.ts
+++ b/packages/browser/src/__tests__/index.test.ts
@@ -1,6 +1,6 @@
 /// <reference types="chrome" />
 import { describe, expectTypeOf, it } from 'vitest';
-import { browser, Browser } from '../index';
+import { browser, type Browser } from '../index';
 
 describe('browser', () => {
   describe('types', () => {
diff --git a/packages/wxt-demo/src/entrypoints/__tests__/background.test.ts b/packages/wxt-demo/src/entrypoints/__tests__/background.test.ts
index 62f79bed..c46f84d2 100644
--- a/packages/wxt-demo/src/entrypoints/__tests__/background.test.ts
+++ b/packages/wxt-demo/src/entrypoints/__tests__/background.test.ts
@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import background from '../background';
 
-chrome.i18n.getMessage = () => 'fake-message';
+browser.i18n.getMessage = () => 'fake-message';
 
 const logMock = vi.fn();
 console.log = logMock;
@@ -11,7 +11,7 @@ describe('Background Entrypoint', () => {
     fakeBrowser.reset();
   });
 
-  it("should log the extenion's runtime ID", () => {
+  it("should log the extension's runtime ID", () => {
     const id = 'some-id';
     fakeBrowser.runtime.id = id;
 
diff --git a/packages/wxt-demo/wxt.config.ts b/packages/wxt-demo/wxt.config.ts
index 6961eea2..eee9f5d3 100644
--- a/packages/wxt-demo/wxt.config.ts
+++ b/packages/wxt-demo/wxt.config.ts
@@ -3,7 +3,6 @@ import { presetUno } from 'unocss';
 
 export default defineConfig({
   srcDir: 'src',
-  extensionApi: 'chrome',
   manifest: {
     permissions: ['storage'],
     default_locale: 'en',
diff --git a/packages/wxt/e2e/tests/modules.test.ts b/packages/wxt/e2e/tests/modules.test.ts
index 11d86688..dcbe6c90 100644
--- a/packages/wxt/e2e/tests/modules.test.ts
+++ b/packages/wxt/e2e/tests/modules.test.ts
@@ -191,10 +191,7 @@ describe('Module Helpers', () => {
       );
       const expectedText = addPluginModule(project);
 
-      await project.build({
-        // reduce build output when comparing test failures
-        extensionApi: 'chrome',
-      });
+      await project.build();
 
       await expect(project.serializeOutput()).resolves.toContain(expectedText);
     });
@@ -211,10 +208,7 @@ describe('Module Helpers', () => {
       );
       const expectedText = addPluginModule(project);
 
-      await project.build({
-        // reduce build output when comparing test failures
-        extensionApi: 'chrome',
-      });
+      await project.build();
 
       await expect(project.serializeOutput()).resolves.toContain(expectedText);
     });
@@ -232,10 +226,7 @@ describe('Module Helpers', () => {
       );
       const expectedText = addPluginModule(project);
 
-      await project.build({
-        // reduce build output when comparing test failures
-        extensionApi: 'chrome',
-      });
+      await project.build();
 
       await expect(project.serializeOutput()).resolves.toContain(expectedText);
     });
@@ -248,10 +239,7 @@ describe('Module Helpers', () => {
       );
       const expectedText = addPluginModule(project);
 
-      await project.build({
-        // reduce build output when comparing test failures
-        extensionApi: 'chrome',
-      });
+      await project.build();
 
       await expect(project.serializeOutput()).resolves.toContain(expectedText);
     });
diff --git a/packages/wxt/e2e/tests/output-structure.test.ts b/packages/wxt/e2e/tests/output-structure.test.ts
index 260157ae..4145eaab 100644
--- a/packages/wxt/e2e/tests/output-structure.test.ts
+++ b/packages/wxt/e2e/tests/output-structure.test.ts
@@ -262,9 +262,6 @@ describe('Output Directory Structure', () => {
     project.addFile('entrypoints/popup/main.ts', `logHello('popup')`);
 
     await project.build({
-      // Simplify the build output for comparison
-      extensionApi: 'chrome',
-
       vite: () => ({
         build: {
           // Make output for snapshot readible
@@ -289,11 +286,7 @@ describe('Output Directory Structure', () => {
             logHello("background");
           }
         });
-        // @ts-expect-error
-        ((_b = (_a = globalThis.browser) == null ? void 0 : _a.runtime) == null ? void 0 : _b.id) == null ? globalThis.chrome : (
-          // @ts-expect-error
-          globalThis.browser
-        );
+        ((_b = (_a = globalThis.browser) == null ? void 0 : _a.runtime) == null ? void 0 : _b.id) ? globalThis.browser : globalThis.chrome;
         function print(method, ...args) {
           return;
         }
@@ -347,9 +340,6 @@ describe('Output Directory Structure', () => {
     project.addFile('entrypoints/popup/main.ts', `logHello('popup')`);
 
     await project.build({
-      // Simplify the build output for comparison
-      extensionApi: 'chrome',
-
       vite: () => ({
         build: {
           // Make output for snapshot readible
@@ -381,11 +371,7 @@ describe('Output Directory Structure', () => {
           background;
           function initPlugins() {
           }
-          // @ts-expect-error
-          ((_b = (_a = globalThis.browser) == null ? void 0 : _a.runtime) == null ? void 0 : _b.id) == null ? globalThis.chrome : (
-            // @ts-expect-error
-            globalThis.browser
-          );
+          ((_b = (_a = globalThis.browser) == null ? void 0 : _a.runtime) == null ? void 0 : _b.id) ? globalThis.browser : globalThis.chrome;
           function print(method, ...args) {
             return;
           }
diff --git a/packages/wxt/e2e/tests/user-config.test.ts b/packages/wxt/e2e/tests/user-config.test.ts
index b120bf87..0ee4a969 100644
--- a/packages/wxt/e2e/tests/user-config.test.ts
+++ b/packages/wxt/e2e/tests/user-config.test.ts
@@ -1,6 +1,5 @@
 import { describe, it, expect } from 'vitest';
 import { TestProject } from '../utils';
-import { InlineConfig } from '../../src/types';
 
 describe('User Config', () => {
   // Root directory is tested with all tests.
@@ -88,24 +87,6 @@ describe('User Config', () => {
     `);
   });
 
-  it('should exclude the polyfill when extensionApi="chrome"', async () => {
-    const buildBackground = async (config?: InlineConfig) => {
-      const background = `export default defineBackground(() => console.log(browser.runtime.id));`;
-      const projectWithPolyfill = new TestProject();
-      projectWithPolyfill.addFile('entrypoints/background.ts', background);
-      await projectWithPolyfill.build(config);
-      return await projectWithPolyfill.serializeFile(
-        '.output/chrome-mv3/background.js',
-      );
-    };
-
-    const withPolyfill = await buildBackground();
-    const withoutPolyfill = await buildBackground({
-      extensionApi: 'chrome',
-    });
-    expect(withoutPolyfill).not.toBe(withPolyfill);
-  });
-
   it('should respect changing config files', async () => {
     const project = new TestProject();
     project.addFile(
diff --git a/packages/wxt/package.json b/packages/wxt/package.json
index 39ca18ad..03583adb 100644
--- a/packages/wxt/package.json
+++ b/packages/wxt/package.json
@@ -47,12 +47,8 @@
       "default": "./dist/sandbox/index.mjs"
     },
     "./browser": {
-      "types": "./dist/browser/index.d.ts",
-      "default": "./dist/browser/index.mjs"
-    },
-    "./browser/chrome": {
-      "types": "./dist/browser/chrome.d.ts",
-      "import": "./dist/browser/chrome.mjs"
+      "types": "./dist/browser.d.ts",
+      "default": "./dist/browser.mjs"
     },
     "./testing": {
       "types": "./dist/testing/index.d.ts",
@@ -84,11 +80,10 @@
   "dependencies": {
     "@1natsu/wait-element": "catalog:",
     "@aklinker1/rollup-plugin-visualizer": "catalog:",
-    "@types/chrome": "catalog:",
-    "@types/webextension-polyfill": "catalog:",
     "@webext-core/fake-browser": "catalog:",
     "@webext-core/isolated-element": "catalog:",
     "@webext-core/match-patterns": "catalog:",
+    "@wxt-dev/browser": "workspace:*",
     "@wxt-dev/storage": "workspace:^1.0.0",
     "async-mutex": "catalog:",
     "c12": "catalog:",
@@ -128,8 +123,7 @@
     "unimport": "catalog:",
     "vite": "catalog:",
     "vite-node": "catalog:",
-    "web-ext-run": "catalog:",
-    "webextension-polyfill": "catalog:"
+    "web-ext-run": "catalog:"
   },
   "devDependencies": {
     "@aklinker1/check": "catalog:",
@@ -149,9 +143,5 @@
     "vitest": "catalog:",
     "vitest-plugin-random-seed": "catalog:"
   },
-  "peerDependenciesMeta": {
-    "@types/chrome": {
-      "optional": true
-    }
-  }
+  "peerDependenciesMeta": {}
 }
diff --git a/packages/wxt/src/browser.ts b/packages/wxt/src/browser.ts
new file mode 100644
index 00000000..9f0b96fd
--- /dev/null
+++ b/packages/wxt/src/browser.ts
@@ -0,0 +1,25 @@
+/**
+ * @module wxt/browser
+ */
+import { browser as _browser, type Browser } from '@wxt-dev/browser';
+
+/**
+ * This interface is empty because it is generated per-project when running `wxt prepare`. See:
+ * - `.wxt/types/paths.d.ts`
+ */
+export interface WxtRuntime {}
+
+/**
+ * This interface is empty because it is generated per-project when running `wxt prepare`. See:
+ * - `.wxt/types/i18n.d.ts`
+ */
+export interface WxtI18n {}
+
+export type WxtBrowser = Omit<typeof _browser, 'runtime' | 'i18n'> & {
+  runtime: WxtRuntime & Omit<(typeof _browser)['runtime'], 'getURL'>;
+  i18n: WxtI18n & Omit<(typeof _browser)['i18n'], 'getMessage'>;
+};
+
+export const browser: WxtBrowser = _browser;
+
+export { Browser };
diff --git a/packages/wxt/src/browser/chrome.ts b/packages/wxt/src/browser/chrome.ts
deleted file mode 100644
index d1dad85d..00000000
--- a/packages/wxt/src/browser/chrome.ts
+++ /dev/null
@@ -1,23 +0,0 @@
-/// <reference types="chrome" />
-/**
- * EXPERIMENTAL
- *
- * Includes the `chrome` API and types when using `extensionApi: 'chrome'`.
- *
- * @module wxt/browser/chrome
- */
-import type { WxtRuntime, WxtI18n } from './index';
-
-export type WxtBrowser = Omit<typeof chrome, 'runtime' | 'i18n'> & {
-  runtime: WxtRuntime & Omit<(typeof chrome)['runtime'], 'getURL'>;
-  i18n: WxtI18n & Omit<(typeof chrome)['i18n'], 'getMessage'>;
-};
-
-// #region snippet
-export const browser: WxtBrowser =
-  // @ts-expect-error
-  globalThis.browser?.runtime?.id == null
-    ? globalThis.chrome
-    : // @ts-expect-error
-      globalThis.browser;
-// #endregion snippet
diff --git a/packages/wxt/src/browser/index.ts b/packages/wxt/src/browser/index.ts
deleted file mode 100644
index 8e21e1fb..00000000
--- a/packages/wxt/src/browser/index.ts
+++ /dev/null
@@ -1,87 +0,0 @@
-/**
- * Includes the `browser` API and types when using `extensionApi: 'webextension-polyfill'` (the default).
- *
- * @module wxt/browser
- */
-
-import originalBrowser, { Browser } from 'webextension-polyfill';
-
-export type AugmentedBrowser = Omit<Browser, 'runtime' | 'i18n'> & {
-  runtime: WxtRuntime & Omit<Browser['runtime'], 'getURL'>;
-  i18n: WxtI18n & Omit<Browser['i18n'], 'getMessage'>;
-};
-
-/**
- * This interface is empty because it is generated per-project when running `wxt prepare`. See:
- * - `.wxt/types/paths.d.ts`
- */
-export interface WxtRuntime {}
-
-/**
- * This interface is empty because it is generated per-project when running `wxt prepare`. See:
- * - `.wxt/types/i18n.d.ts`
- */
-export interface WxtI18n {}
-
-export const browser: AugmentedBrowser = originalBrowser;
-
-// re-export all the types from webextension-polyfill
-// Because webextension-polyfill uses a weird namespace with "import export", there isn't a good way
-// to get these types without re-listing them.
-/** @ignore */
-export type {
-  ActivityLog,
-  Alarms,
-  Bookmarks,
-  Action,
-  BrowserAction,
-  BrowserSettings,
-  BrowsingData,
-  CaptivePortal,
-  Clipboard,
-  Commands,
-  ContentScripts,
-  ContextualIdentities,
-  Cookies,
-  DeclarativeNetRequest,
-  Devtools,
-  Dns,
-  Downloads,
-  Events,
-  Experiments,
-  Extension,
-  ExtensionTypes,
-  Find,
-  GeckoProfiler,
-  History,
-  I18n,
-  Identity,
-  Idle,
-  Management,
-  Manifest, // TODO: Export custom manifest types that are valid for both Chrome and Firefox.
-  ContextMenus,
-  Menus,
-  NetworkStatus,
-  NormandyAddonStudy,
-  Notifications,
-  Omnibox,
-  PageAction,
-  Permissions,
-  Pkcs11,
-  Privacy,
-  Proxy,
-  Runtime,
-  Scripting,
-  Search,
-  Sessions,
-  SidebarAction,
-  Storage,
-  Tabs,
-  Theme,
-  TopSites,
-  Types,
-  UserScripts,
-  WebNavigation,
-  WebRequest,
-  Windows,
-} from 'webextension-polyfill';
diff --git a/packages/wxt/src/client/content-scripts/__tests__/content-script-context.test.ts b/packages/wxt/src/client/content-scripts/__tests__/content-script-context.test.ts
index 23ff12e8..548beb3d 100644
--- a/packages/wxt/src/client/content-scripts/__tests__/content-script-context.test.ts
+++ b/packages/wxt/src/client/content-scripts/__tests__/content-script-context.test.ts
@@ -24,7 +24,7 @@ describe('Content Script Context', () => {
     const onInvalidated = vi.fn();
 
     ctx.onInvalidated(onInvalidated);
-    // @ts-expect-error
+    // @ts-ignore
     delete fakeBrowser.runtime.id;
     const isValid = ctx.isValid;
 
diff --git a/packages/wxt/src/core/builders/vite/index.ts b/packages/wxt/src/core/builders/vite/index.ts
index 545c6339..24bbe5d9 100644
--- a/packages/wxt/src/core/builders/vite/index.ts
+++ b/packages/wxt/src/core/builders/vite/index.ts
@@ -83,7 +83,6 @@ export async function createViteBuilder(
       wxtPlugins.tsconfigPaths(wxtConfig),
       wxtPlugins.noopBackground(),
       wxtPlugins.globals(wxtConfig),
-      wxtPlugins.resolveExtensionApi(wxtConfig),
       wxtPlugins.defineImportMeta(),
       wxtPlugins.wxtPluginLoader(wxtConfig),
       wxtPlugins.resolveAppConfig(wxtConfig),
diff --git a/packages/wxt/src/core/builders/vite/plugins/extensionApiMock.ts b/packages/wxt/src/core/builders/vite/plugins/extensionApiMock.ts
index 7724219e..0e2b18f3 100644
--- a/packages/wxt/src/core/builders/vite/plugins/extensionApiMock.ts
+++ b/packages/wxt/src/core/builders/vite/plugins/extensionApiMock.ts
@@ -3,12 +3,7 @@ import type * as vite from 'vite';
 import { ResolvedConfig } from '../../../../types';
 
 /**
- * Mock `webextension-polyfill`, `wxt/browser`, and `wxt/browser/*` by inlining
- * all dependencies that import them and adding a custom alias so that Vite
- * resolves to a mocked version of the module.
- *
- * TODO: Detect non-wxt dependencies (like `@webext-core/*`) that import `webextension-polyfill` via
- * `npm list` and inline them automatically.
+ * Mock `wxt/browser` and stub the global `browser`/`chrome` types with a fake version of the extension APIs
  */
 export function extensionApiMock(config: ResolvedConfig): vite.PluginOption {
   const virtualSetupModule = 'virtual:wxt-setup';
@@ -27,14 +22,12 @@ export function extensionApiMock(config: ResolvedConfig): vite.PluginOption {
         },
         resolve: {
           alias: [
-            { find: 'webextension-polyfill', replacement },
             // wxt/browser, wxt/browser/...
-            { find: /^wxt\/browser.*/, replacement },
+            { find: 'wxt/browser', replacement },
           ],
         },
         ssr: {
-          // Inline all WXT modules so vite processes them so the aliases can
-          // be resolved
+          // Inline all WXT modules subdependencies can be mocked
           noExternal: ['wxt'],
         },
       };
diff --git a/packages/wxt/src/core/builders/vite/plugins/index.ts b/packages/wxt/src/core/builders/vite/plugins/index.ts
index f70dde24..5ed13ff8 100644
--- a/packages/wxt/src/core/builders/vite/plugins/index.ts
+++ b/packages/wxt/src/core/builders/vite/plugins/index.ts
@@ -9,7 +9,6 @@ export * from './cssEntrypoints';
 export * from './bundleAnalysis';
 export * from './globals';
 export * from './extensionApiMock';
-export * from './resolveExtensionApi';
 export * from './entrypointGroupGlobals';
 export * from './defineImportMeta';
 export * from './removeEntrypointMainFunction';
diff --git a/packages/wxt/src/core/builders/vite/plugins/resolveExtensionApi.ts b/packages/wxt/src/core/builders/vite/plugins/resolveExtensionApi.ts
deleted file mode 100644
index 17ec0206..00000000
--- a/packages/wxt/src/core/builders/vite/plugins/resolveExtensionApi.ts
+++ /dev/null
@@ -1,27 +0,0 @@
-import { ResolvedConfig } from '../../../../types';
-import type * as vite from 'vite';
-
-/**
- * Apply the experimental config for which extension API is used. This only
- * effects the extension API included at RUNTIME - during development, types
- * depend on the import.
- *
- * NOTE: this only works if we import `wxt/browser` instead of using the relative path.
- */
-export function resolveExtensionApi(config: ResolvedConfig): vite.Plugin {
-  return {
-    name: 'wxt:resolve-extension-api',
-    config() {
-      // Only apply the config if we're disabling the polyfill
-      if (config.extensionApi === 'webextension-polyfill') return;
-
-      return {
-        resolve: {
-          alias: [
-            { find: /^wxt\/browser$/, replacement: 'wxt/browser/chrome' },
-          ],
-        },
-      };
-    },
-  };
-}
diff --git a/packages/wxt/src/core/generate-wxt-dir.ts b/packages/wxt/src/core/generate-wxt-dir.ts
index e7d35949..3e58d778 100644
--- a/packages/wxt/src/core/generate-wxt-dir.ts
+++ b/packages/wxt/src/core/generate-wxt-dir.ts
@@ -37,11 +37,6 @@ export async function generateWxtDir(entrypoints: Entrypoint[]): Promise<void> {
   // import.meta.env.*
   entries.push(await getGlobalsDeclarationEntry());
 
-  // @types/chrome
-  if (wxt.config.extensionApi === 'chrome') {
-    entries.push({ module: '@types/chrome' });
-  }
-
   // tsconfig.json
   entries.push(await getTsConfigEntry());
 
diff --git a/packages/wxt/src/core/resolve-config.ts b/packages/wxt/src/core/resolve-config.ts
index 01c38ca2..d5a9b15a 100644
--- a/packages/wxt/src/core/resolve-config.ts
+++ b/packages/wxt/src/core/resolve-config.ts
@@ -171,8 +171,6 @@ export async function resolveConfig(
     {},
   );
 
-  const extensionApi = mergedConfig.extensionApi ?? 'webextension-polyfill';
-
   return {
     browser,
     command,
@@ -182,13 +180,7 @@ export async function resolveConfig(
     filterEntrypoints,
     env,
     fsCache: createFsCache(wxtDir),
-    imports: await getUnimportOptions(
-      wxtDir,
-      srcDir,
-      logger,
-      extensionApi,
-      mergedConfig,
-    ),
+    imports: await getUnimportOptions(wxtDir, srcDir, logger, mergedConfig),
     logger,
     manifest: await resolveManifestConfig(env, mergedConfig.manifest),
     manifestVersion,
@@ -207,7 +199,6 @@ export async function resolveConfig(
     analysis: resolveAnalysisConfig(root, mergedConfig),
     userConfigMetadata: userConfigMetadata ?? {},
     alias,
-    extensionApi,
     entrypointLoader: mergedConfig.entrypointLoader ?? 'vite-node',
     experimental: defu(mergedConfig.experimental, {}),
     dev: {
@@ -342,7 +333,6 @@ async function getUnimportOptions(
   wxtDir: string,
   srcDir: string,
   logger: Logger,
-  extensionApi: ResolvedConfig['extensionApi'],
   config: InlineConfig,
 ): Promise<WxtResolvedUnimportOptions | false> {
   if (config.imports === false) return false;
@@ -361,10 +351,7 @@ async function getUnimportOptions(
         // ignored.
         ignore: ['options'],
       },
-      {
-        package:
-          extensionApi === 'chrome' ? 'wxt/browser/chrome' : 'wxt/browser',
-      },
+      { package: 'wxt/browser' },
       { package: 'wxt/sandbox' },
       { package: 'wxt/storage' },
     ],
diff --git a/packages/wxt/src/core/utils/__tests__/manifest.test.ts b/packages/wxt/src/core/utils/__tests__/manifest.test.ts
index 230f1470..1a767d10 100644
--- a/packages/wxt/src/core/utils/__tests__/manifest.test.ts
+++ b/packages/wxt/src/core/utils/__tests__/manifest.test.ts
@@ -13,7 +13,6 @@ import {
   fakeWxtDevServer,
   setFakeWxt,
 } from '../testing/fake-objects';
-import { Manifest } from 'webextension-polyfill';
 import {
   BuildOutput,
   ContentScriptEntrypoint,
@@ -22,6 +21,7 @@ import {
 } from '../../../types';
 import { wxt } from '../../wxt';
 import { mock } from 'vitest-mock-extended';
+import type { Browser } from '@wxt-dev/browser';
 
 const outDir = '/output';
 const contentScriptOutDir = '/output/content-scripts';
@@ -58,7 +58,7 @@ describe('Manifest Utils', () => {
             outDir,
           },
         });
-        const expected: Partial<Manifest.WebExtensionManifest> = {
+        const expected: Partial<Browser.runtime.Manifest> = {
           action: {
             default_icon: popup.options.defaultIcon,
             default_title: popup.options.defaultTitle,
diff --git a/packages/wxt/src/core/utils/building/rebuild.ts b/packages/wxt/src/core/utils/building/rebuild.ts
index 7a17e3ff..b0902f5c 100644
--- a/packages/wxt/src/core/utils/building/rebuild.ts
+++ b/packages/wxt/src/core/utils/building/rebuild.ts
@@ -1,9 +1,9 @@
-import type { Manifest } from 'wxt/browser';
 import { BuildOutput, Entrypoint, EntrypointGroup } from '../../../types';
 import { generateWxtDir } from '../../generate-wxt-dir';
 import { buildEntrypoints } from './build-entrypoints';
 import { generateManifest, writeManifest } from '../../utils/manifest';
 import { wxt } from '../../wxt';
+import type { Browser } from '@wxt-dev/browser';
 
 /**
  * Given a configuration, list of entrypoints, and an existing, partial output, build the
@@ -30,7 +30,7 @@ export async function rebuild(
   },
 ): Promise<{
   output: BuildOutput;
-  manifest: Manifest.WebExtensionManifest;
+  manifest: Browser.runtime.Manifest;
   warnings: any[][];
 }> {
   const { default: ora } = await import('ora');
diff --git a/packages/wxt/src/core/utils/content-scripts.ts b/packages/wxt/src/core/utils/content-scripts.ts
index 3ba1eb18..93f00d8a 100644
--- a/packages/wxt/src/core/utils/content-scripts.ts
+++ b/packages/wxt/src/core/utils/content-scripts.ts
@@ -1,6 +1,7 @@
-import type { Manifest, Scripting } from 'wxt/browser';
+import type { Browser } from '@wxt-dev/browser';
 import { ContentScriptEntrypoint, ResolvedConfig } from '../../types';
 import { getEntrypointBundlePath } from './entrypoints';
+import { ManifestContentScript } from './types';
 
 /**
  * Returns a unique and consistent string hash based on a content scripts options.
@@ -22,13 +23,14 @@ export function hashContentScriptOptions(
     if (simplifiedOptions[key] == null) delete simplifiedOptions[key];
   });
 
-  const withDefaults: Manifest.ContentScript = {
+  const withDefaults: ManifestContentScript = {
     exclude_globs: [],
     exclude_matches: [],
     include_globs: [],
     match_about_blank: false,
     run_at: 'document_idle',
     all_frames: false,
+    // @ts-expect-error: Untyped
     match_origin_as_fallback: false,
     world: 'ISOLATED',
     ...simplifiedOptions,
@@ -49,7 +51,7 @@ export function mapWxtOptionsToContentScript(
   options: ContentScriptEntrypoint['options'],
   js: string[] | undefined,
   css: string[] | undefined,
-): Manifest.ContentScript {
+): ManifestContentScript {
   return {
     matches: options.matches ?? [],
     all_frames: options.allFrames,
@@ -61,6 +63,7 @@ export function mapWxtOptionsToContentScript(
     css,
     js,
 
+    // @ts-expect-error: Untyped
     match_origin_as_fallback: options.matchOriginAsFallback,
     world: options.world,
   };
@@ -70,7 +73,7 @@ export function mapWxtOptionsToRegisteredContentScript(
   options: ContentScriptEntrypoint['options'],
   js: string[] | undefined,
   css: string[] | undefined,
-): Omit<Scripting.RegisteredContentScript, 'id'> {
+): Omit<Browser.scripting.RegisteredContentScript, 'id'> {
   return {
     allFrames: options.allFrames,
     excludeMatches: options.excludeMatches,
diff --git a/packages/wxt/src/core/utils/manifest.ts b/packages/wxt/src/core/utils/manifest.ts
index 364f749f..7b0d3388 100644
--- a/packages/wxt/src/core/utils/manifest.ts
+++ b/packages/wxt/src/core/utils/manifest.ts
@@ -1,4 +1,3 @@
-import type { Manifest } from 'wxt/browser';
 import {
   Entrypoint,
   BackgroundEntrypoint,
@@ -21,12 +20,14 @@ import { normalizePath } from './paths';
 import { writeFileIfDifferent } from './fs';
 import defu from 'defu';
 import { wxt } from '../wxt';
+import { ManifestV3WebAccessibleResource } from './types';
+import type { Browser } from '@wxt-dev/browser';
 
 /**
  * Writes the manifest to the output directory and the build output.
  */
 export async function writeManifest(
-  manifest: Manifest.WebExtensionManifest,
+  manifest: Browser.runtime.Manifest,
   output: BuildOutput,
 ): Promise<void> {
   const str =
@@ -49,7 +50,7 @@ export async function writeManifest(
 export async function generateManifest(
   allEntrypoints: Entrypoint[],
   buildOutput: Omit<BuildOutput, 'manifest'>,
-): Promise<{ manifest: Manifest.WebExtensionManifest; warnings: any[][] }> {
+): Promise<{ manifest: Browser.runtime.Manifest; warnings: any[][] }> {
   const entrypoints = allEntrypoints.filter((entry) => !entry.skipped);
 
   const warnings: any[][] = [];
@@ -67,7 +68,7 @@ export async function generateManifest(
   }
   const version = wxt.config.manifest.version ?? simplifyVersion(versionName);
 
-  const baseManifest: Manifest.WebExtensionManifest = {
+  const baseManifest: Browser.runtime.Manifest = {
     manifest_version: wxt.config.manifestVersion,
     name: pkg?.name,
     description: pkg?.description,
@@ -83,10 +84,7 @@ export async function generateManifest(
     );
   }
 
-  let manifest = defu(
-    userManifest,
-    baseManifest,
-  ) as Manifest.WebExtensionManifest;
+  let manifest = defu(userManifest, baseManifest) as Browser.runtime.Manifest;
 
   // Add reload command in dev mode
   if (wxt.config.command === 'serve' && wxt.config.dev.reloadCommand) {
@@ -177,7 +175,7 @@ function simplifyVersion(versionName: string): string {
 }
 
 function addEntrypoints(
-  manifest: Manifest.WebExtensionManifest,
+  manifest: Browser.runtime.Manifest,
   entrypoints: Entrypoint[],
   buildOutput: Omit<BuildOutput, 'manifest'>,
 ): void {
@@ -239,7 +237,6 @@ function addEntrypoints(
       );
     } else {
       manifest.chrome_url_overrides ??= {};
-      // @ts-expect-error: bookmarks is untyped in webextension-polyfill, but supported by chrome
       manifest.chrome_url_overrides.bookmarks = getEntrypointBundlePath(
         bookmarks,
         wxt.config.outDir,
@@ -255,7 +252,6 @@ function addEntrypoints(
       );
     } else {
       manifest.chrome_url_overrides ??= {};
-      // @ts-expect-error: history is untyped in webextension-polyfill, but supported by chrome
       manifest.chrome_url_overrides.history = getEntrypointBundlePath(
         history,
         wxt.config.outDir,
@@ -279,12 +275,13 @@ function addEntrypoints(
       wxt.config.outDir,
       '.html',
     );
-    const options: Manifest.ActionManifest = {};
+    const options: Browser.runtime.ManifestAction = {};
     if (popup.options.defaultIcon)
       options.default_icon = popup.options.defaultIcon;
     if (popup.options.defaultTitle)
       options.default_title = popup.options.defaultTitle;
     if (popup.options.browserStyle)
+      // @ts-expect-error: Not typed by @wxt-dev/browser, but supported by Firefox
       options.browser_style = popup.options.browserStyle;
     if (manifest.manifest_version === 3) {
       manifest.action = {
@@ -314,6 +311,7 @@ function addEntrypoints(
     const page = getEntrypointBundlePath(options, wxt.config.outDir, '.html');
     manifest.options_ui = {
       open_in_tab: options.options.openInTab,
+      // @ts-expect-error: Not typed by @wxt-dev/browser, but supported by Firefox
       browser_style:
         wxt.config.browser === 'firefox'
           ? options.options.browserStyle
@@ -332,7 +330,6 @@ function addEntrypoints(
         'Sandboxed pages not supported by Firefox. sandbox.pages was not added to the manifest',
       );
     } else {
-      // @ts-expect-error: sandbox not typed
       manifest.sandbox = {
         pages: sandboxes.map((entry) =>
           getEntrypointBundlePath(entry, wxt.config.outDir, '.html'),
@@ -359,7 +356,6 @@ function addEntrypoints(
         open_at_install: defaultSidepanel.options.openAtInstall,
       };
     } else if (wxt.config.manifestVersion === 3) {
-      // @ts-expect-error: Untyped
       manifest.side_panel = {
         default_path: page,
       };
@@ -432,7 +428,7 @@ function addEntrypoints(
 
 function discoverIcons(
   buildOutput: Omit<BuildOutput, 'manifest'>,
-): Manifest.WebExtensionManifest['icons'] {
+): Browser.runtime.Manifest['icons'] {
   const icons: [string, string][] = [];
   // prettier-ignore
   // #region snippet
@@ -464,7 +460,7 @@ function discoverIcons(
   return icons.length > 0 ? Object.fromEntries(icons) : undefined;
 }
 
-function addDevModeCsp(manifest: Manifest.WebExtensionManifest): void {
+function addDevModeCsp(manifest: Browser.runtime.Manifest): void {
   const permission = `http://${wxt.server?.hostname ?? ''}/*`;
   const allowedCsp = wxt.server?.origin ?? 'http://localhost:*';
 
@@ -499,7 +495,7 @@ function addDevModeCsp(manifest: Manifest.WebExtensionManifest): void {
   manifest.content_security_policy.sandbox = sandboxCsp.toString();
 }
 
-function addDevModePermissions(manifest: Manifest.WebExtensionManifest) {
+function addDevModePermissions(manifest: Browser.runtime.Manifest) {
   // For reloading the page
   addPermission(manifest, 'tabs');
 
@@ -543,8 +539,7 @@ export function getContentScriptCssWebAccessibleResources(
   contentScripts: ContentScriptEntrypoint[],
   contentScriptCssMap: Record<string, string | undefined>,
 ): any[] {
-  const resources: Manifest.WebExtensionManifestWebAccessibleResourcesC2ItemType[] =
-    [];
+  const resources: ManifestV3WebAccessibleResource[] = [];
 
   contentScripts.forEach((script) => {
     if (script.options.cssInjectionMode !== 'ui') return;
@@ -554,9 +549,10 @@ export function getContentScriptCssWebAccessibleResources(
 
     resources.push({
       resources: [cssFile],
-      matches: script.options.matches?.map((matchPattern) =>
-        stripPathFromMatchPattern(matchPattern),
-      ),
+      matches:
+        script.options.matches?.map((matchPattern) =>
+          stripPathFromMatchPattern(matchPattern),
+        ) ?? [],
     });
   });
 
@@ -583,16 +579,18 @@ export function getContentScriptsCssMap(
 }
 
 function addPermission(
-  manifest: Manifest.WebExtensionManifest,
+  manifest: Browser.runtime.Manifest,
   permission: string,
 ): void {
   manifest.permissions ??= [];
+  // @ts-expect-error: Allow using strings for permissions for MV2 support
   if (manifest.permissions.includes(permission)) return;
+  // @ts-expect-error: Allow using strings for permissions for MV2 support
   manifest.permissions.push(permission);
 }
 
 function addHostPermission(
-  manifest: Manifest.WebExtensionManifest,
+  manifest: Browser.runtime.Manifest,
   hostPermission: string,
 ): void {
   manifest.host_permissions ??= [];
@@ -618,7 +616,7 @@ export function stripPathFromMatchPattern(pattern: string) {
  * targeting MV2, automatically convert their definitions down to the basic MV2 array.
  */
 export function convertWebAccessibleResourcesToMv2(
-  manifest: Manifest.WebExtensionManifest,
+  manifest: Browser.runtime.Manifest,
 ): void {
   if (manifest.web_accessible_resources == null) return;
 
@@ -633,17 +631,17 @@ export function convertWebAccessibleResourcesToMv2(
 }
 
 function moveHostPermissionsToPermissions(
-  manifest: Manifest.WebExtensionManifest,
+  manifest: Browser.runtime.Manifest,
 ): void {
   if (!manifest.host_permissions?.length) return;
 
-  manifest.host_permissions.forEach((permission) =>
+  manifest.host_permissions.forEach((permission: string) =>
     addPermission(manifest, permission),
   );
   delete manifest.host_permissions;
 }
 
-function convertActionToMv2(manifest: Manifest.WebExtensionManifest): void {
+function convertActionToMv2(manifest: Browser.runtime.Manifest): void {
   if (
     manifest.action == null ||
     manifest.browser_action != null ||
@@ -654,7 +652,7 @@ function convertActionToMv2(manifest: Manifest.WebExtensionManifest): void {
   manifest.browser_action = manifest.action;
 }
 
-function convertCspToMv2(manifest: Manifest.WebExtensionManifest): void {
+function convertCspToMv2(manifest: Browser.runtime.Manifest): void {
   if (
     typeof manifest.content_security_policy === 'string' ||
     manifest.content_security_policy?.extension_pages == null
@@ -668,8 +666,8 @@ function convertCspToMv2(manifest: Manifest.WebExtensionManifest): void {
 /**
  * Make sure all resources are in MV3 format. If not, add a wanring
  */
-export function validateMv3WebAccessibleResources(
-  manifest: Manifest.WebExtensionManifest,
+function validateMv3WebAccessibleResources(
+  manifest: Browser.runtime.Manifest,
 ): void {
   if (manifest.web_accessible_resources == null) return;
 
@@ -688,7 +686,7 @@ export function validateMv3WebAccessibleResources(
 /**
  * Remove keys from the manifest based on the build target.
  */
-function stripKeys(manifest: Manifest.WebExtensionManifest): void {
+function stripKeys(manifest: Browser.runtime.Manifest): void {
   let keysToRemove: string[] = [];
   if (wxt.config.manifestVersion === 2) {
     keysToRemove.push(...mv3OnlyKeys);
@@ -699,7 +697,7 @@ function stripKeys(manifest: Manifest.WebExtensionManifest): void {
   }
 
   keysToRemove.forEach((key) => {
-    delete manifest[key as keyof Manifest.WebExtensionManifest];
+    delete manifest[key as keyof Browser.runtime.Manifest];
   });
 }
 
diff --git a/packages/wxt/src/core/utils/testing/fake-objects.ts b/packages/wxt/src/core/utils/testing/fake-objects.ts
index 0586d7fb..eeef953b 100644
--- a/packages/wxt/src/core/utils/testing/fake-objects.ts
+++ b/packages/wxt/src/core/utils/testing/fake-objects.ts
@@ -4,7 +4,6 @@
 import { resolve } from 'path';
 import { faker } from '@faker-js/faker';
 import merge from 'lodash.merge';
-import type { Manifest } from 'wxt/browser';
 import {
   FsCache,
   ResolvedConfig,
@@ -27,6 +26,7 @@ import {
 import { mock } from 'vitest-mock-extended';
 import { vi } from 'vitest';
 import { setWxtForTesting } from '../../../core/wxt';
+import type { Browser } from '@wxt-dev/browser';
 
 faker.seed(import.meta.test.SEED);
 
@@ -208,13 +208,11 @@ export function fakeOutputFile(): OutputFile {
   return faker.helpers.arrayElement([fakeOutputAsset(), fakeOutputChunk()]);
 }
 
-export const fakeManifest = fakeObjectCreator<Manifest.WebExtensionManifest>(
-  () => ({
-    manifest_version: faker.helpers.arrayElement([2, 3]),
-    name: faker.string.alphanumeric(),
-    version: `${faker.number.int()}.${faker.number.int()}.${faker.number.int()}`,
-  }),
-);
+export const fakeManifest = fakeObjectCreator<Browser.runtime.Manifest>(() => ({
+  manifest_version: faker.helpers.arrayElement([2, 3]),
+  name: faker.string.alphanumeric(),
+  version: `${faker.number.int()}.${faker.number.int()}.${faker.number.int()}`,
+}));
 
 export const fakeUserManifest = fakeObjectCreator<UserManifest>(() => ({
   name: faker.string.alphanumeric(),
@@ -299,7 +297,6 @@ export const fakeResolvedConfig = fakeObjectCreator<ResolvedConfig>(() => {
     transformManifest: () => {},
     userConfigMetadata: {},
     alias: {},
-    extensionApi: 'webextension-polyfill',
     entrypointLoader: 'vite-node',
     experimental: {},
     dev: {
@@ -356,8 +353,8 @@ export const fakeBuildStepOutput = fakeObjectCreator<BuildStepOutput>(() => ({
   entrypoints: fakeArray(fakeEntrypoint),
 }));
 
-export const fakeManifestCommand =
-  fakeObjectCreator<Manifest.WebExtensionManifestCommandsType>(() => ({
+export const fakeManifestCommand = fakeObjectCreator<Browser.commands.Command>(
+  () => ({
     description: faker.string.sample(),
     suggested_key: {
       default: `${faker.helpers.arrayElement(['ctrl', 'alt'])}+${faker.number.int(
@@ -367,7 +364,8 @@ export const fakeManifestCommand =
         },
       )}`,
     },
-  }));
+  }),
+);
 
 export const fakeDevServer = fakeObjectCreator<WxtDevServer>(() => ({
   hostname: 'localhost',
diff --git a/packages/wxt/src/core/utils/transform.ts b/packages/wxt/src/core/utils/transform.ts
index f6951c61..857fdcff 100644
--- a/packages/wxt/src/core/utils/transform.ts
+++ b/packages/wxt/src/core/utils/transform.ts
@@ -5,7 +5,7 @@ import { ProxifiedModule, parseModule } from 'magicast';
  * 1. Removes or clears out `main` function from returned object
  * 2. Removes any unused functions/variables outside the definition that aren't being called/used
  * 3. Removes unused imports
- * 3. Removes value-less, side-effect only imports (like `import "./styles.css"` or `import "webextension-polyfill"`)
+ * 3. Removes value-less, side-effect only imports (like `import "./styles.css"` or `import "polyfill"`)
  */
 export function removeMainFunctionCode(code: string): {
   code: string;
diff --git a/packages/wxt/src/core/utils/types.ts b/packages/wxt/src/core/utils/types.ts
index ed6ff200..9755088a 100644
--- a/packages/wxt/src/core/utils/types.ts
+++ b/packages/wxt/src/core/utils/types.ts
@@ -1,3 +1,5 @@
+import type { Browser } from '@wxt-dev/browser';
+
 /**
  * Remove optional from key, but keep undefined if present
  *
@@ -6,3 +8,11 @@
  * // type Test = {a: string | undefined, b: number}
  */
 export type NullablyRequired<T> = { [K in keyof Required<T>]: T[K] };
+
+export type ManifestContentScript = NonNullable<
+  Browser.runtime.Manifest['content_scripts']
+>[number];
+
+export type ManifestV3WebAccessibleResource = NonNullable<
+  Browser.runtime.ManifestV3['web_accessible_resources']
+>[number];
diff --git a/packages/wxt/src/types.ts b/packages/wxt/src/types.ts
index 187ecb1f..1d6f29bf 100644
--- a/packages/wxt/src/types.ts
+++ b/packages/wxt/src/types.ts
@@ -1,5 +1,4 @@
 import type * as vite from 'vite';
-import type { Manifest, Scripting } from 'wxt/browser';
 import { UnimportOptions, Import } from 'unimport';
 import { LogLevel } from 'consola';
 import type { ContentScriptContext } from './client/content-scripts/content-script-context';
@@ -7,6 +6,8 @@ import type { PluginVisualizerOptions } from '@aklinker1/rollup-plugin-visualize
 import { ResolvedConfig as C12ResolvedConfig } from 'c12';
 import { Hookable, NestedHooks } from 'hookable';
 import type * as Nypm from 'nypm';
+import { ManifestContentScript } from './core/utils/types';
+import type { Browser } from '@wxt-dev/browser';
 
 export interface InlineConfig {
   /**
@@ -267,7 +268,7 @@ export interface InlineConfig {
    *   }
    * })
    */
-  transformManifest?: (manifest: Manifest.WebExtensionManifest) => void;
+  transformManifest?: (manifest: Browser.runtime.Manifest) => void;
   analysis?: {
     /**
      * Explicitly include bundle analysis when running `wxt build`. This can be overridden by the
@@ -325,16 +326,6 @@ export interface InlineConfig {
    * }
    */
   alias?: Record<string, string>;
-  /**
-   * Which extension API to use.
-   *
-   * - `"webextension-polyfill"`: Use `browser` and types from [`webextension-polyfill`](https://www.npmjs.com/package/webextension-polyfill).
-   * - `"chrome"`: Use the regular `chrome` (or `browser` for Firefox/Safari) globals provided by the browser. Types provided by [`@types/chrome`](https://www.npmjs.com/package/@types/chrome).
-   *
-   * @default "webextension-polyfill"
-   * @since 0.19.0
-   */
-  extensionApi?: 'webextension-polyfill' | 'chrome';
   /**
    * @deprecated Will be removed in v0.20.0, please migrate to using `vite-node`, the new default.
    *
@@ -444,7 +435,7 @@ export interface WxtHooks {
 }
 
 export interface BuildOutput {
-  manifest: Manifest.WebExtensionManifest;
+  manifest: Browser.runtime.Manifest;
   publicAssets: OutputAsset[];
   steps: BuildStepOutput[];
 }
@@ -537,7 +528,7 @@ export interface WxtDevServer
 
 export interface ReloadContentScriptPayload {
   registration?: BaseContentScriptEntrypointOptions['registration'];
-  contentScript: Omit<Scripting.RegisteredContentScript, 'id'>;
+  contentScript: Omit<Browser.scripting.RegisteredContentScript, 'id'>;
 }
 
 export type TargetBrowser = string;
@@ -588,39 +579,39 @@ export interface BackgroundEntrypointOptions extends BaseEntrypointOptions {
 
 export interface BaseContentScriptEntrypointOptions
   extends BaseEntrypointOptions {
-  matches?: PerBrowserOption<Manifest.ContentScript['matches']>;
+  matches?: PerBrowserOption<NonNullable<ManifestContentScript['matches']>>;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default "documentIdle"
    */
-  runAt?: PerBrowserOption<Manifest.ContentScript['run_at']>;
+  runAt?: PerBrowserOption<Browser.scripting.RegisteredContentScript['runAt']>;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default false
    */
   matchAboutBlank?: PerBrowserOption<
-    Manifest.ContentScript['match_about_blank']
+    ManifestContentScript['match_about_blank']
   >;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default []
    */
-  excludeMatches?: PerBrowserOption<Manifest.ContentScript['exclude_matches']>;
+  excludeMatches?: PerBrowserOption<ManifestContentScript['exclude_matches']>;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default []
    */
-  includeGlobs?: PerBrowserOption<Manifest.ContentScript['include_globs']>;
+  includeGlobs?: PerBrowserOption<ManifestContentScript['include_globs']>;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default []
    */
-  excludeGlobs?: PerBrowserOption<Manifest.ContentScript['exclude_globs']>;
+  excludeGlobs?: PerBrowserOption<ManifestContentScript['exclude_globs']>;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default false
    */
-  allFrames?: PerBrowserOption<Manifest.ContentScript['all_frames']>;
+  allFrames?: PerBrowserOption<ManifestContentScript['all_frames']>;
   /**
    * See https://developer.chrome.com/docs/extensions/mv3/content_scripts/
    * @default false
@@ -868,7 +859,7 @@ export type ResolvedPerBrowserOptions<T, TOmitted extends keyof T = never> = {
  * here, they are configured inline.
  */
 export type UserManifest = {
-  [key in keyof chrome.runtime.ManifestV3 as key extends
+  [key in keyof Browser.runtime.ManifestV3 as key extends
     | 'action'
     | 'background'
     | 'chrome_url_overrides'
@@ -880,16 +871,16 @@ export type UserManifest = {
     | 'sandbox'
     | 'web_accessible_resources'
     ? never
-    : key]?: chrome.runtime.ManifestV3[key];
+    : key]?: Browser.runtime.ManifestV3[key];
 } & {
   // Add any Browser-specific or MV2 properties that WXT supports here
-  action?: chrome.runtime.ManifestV3['action'] & {
+  action?: Browser.runtime.ManifestV3['action'] & {
     browser_style?: boolean;
   };
-  browser_action?: chrome.runtime.ManifestV2['browser_action'] & {
+  browser_action?: Browser.runtime.ManifestV2['browser_action'] & {
     browser_style?: boolean;
   };
-  page_action?: chrome.runtime.ManifestV2['page_action'] & {
+  page_action?: Browser.runtime.ManifestV2['page_action'] & {
     browser_style?: boolean;
   };
   browser_specific_settings?: {
@@ -909,12 +900,12 @@ export type UserManifest = {
     };
   };
   permissions?: (
-    | chrome.runtime.ManifestPermissions
+    | Browser.runtime.ManifestPermissions
     | (string & Record<never, never>)
   )[];
   web_accessible_resources?:
     | string[]
-    | chrome.runtime.ManifestV3['web_accessible_resources'];
+    | Browser.runtime.ManifestV3['web_accessible_resources'];
 };
 
 export type UserManifestFn = (
@@ -1187,7 +1178,7 @@ export interface WxtHooks {
    */
   'build:manifestGenerated': (
     wxt: Wxt,
-    manifest: Manifest.WebExtensionManifest,
+    manifest: Browser.runtime.Manifest,
   ) => HookResult;
   /**
    * Called once the names and paths of all entrypoints have been resolved.
@@ -1359,7 +1350,7 @@ export interface ResolvedConfig {
   /**
    * @deprecated Use `build:manifestGenerated` hook instead.
    */
-  transformManifest?: (manifest: Manifest.WebExtensionManifest) => void;
+  transformManifest?: (manifest: Browser.runtime.Manifest) => void;
   analysis: {
     enabled: boolean;
     open: boolean;
@@ -1377,7 +1368,6 @@ export interface ResolvedConfig {
    * Import aliases to absolute paths.
    */
   alias: Record<string, string>;
-  extensionApi: 'webextension-polyfill' | 'chrome';
   entrypointLoader: 'vite-node' | 'jiti';
   experimental: {};
   dev: {
diff --git a/packages/wxt/src/virtual/utils/reload-content-scripts.ts b/packages/wxt/src/virtual/utils/reload-content-scripts.ts
index 11b5e0c8..3b82417a 100644
--- a/packages/wxt/src/virtual/utils/reload-content-scripts.ts
+++ b/packages/wxt/src/virtual/utils/reload-content-scripts.ts
@@ -84,7 +84,7 @@ async function reloadTabsForContentScript(contentScript: ContentScript) {
   await Promise.all(
     matchingTabs.map(async (tab) => {
       try {
-        await browser.tabs.reload(tab.id);
+        await browser.tabs.reload(tab.id!);
       } catch (err) {
         logger.warn('Failed to reload tab:', err);
       }
diff --git a/packages/wxt/src/virtual/virtual-module-globals.d.ts b/packages/wxt/src/virtual/virtual-module-globals.d.ts
index 5199a83a..0b70bcf1 100644
--- a/packages/wxt/src/virtual/virtual-module-globals.d.ts
+++ b/packages/wxt/src/virtual/virtual-module-globals.d.ts
@@ -21,7 +21,7 @@ declare module 'virtual:user-unlisted-script-entrypoint' {
 }
 
 declare module 'wxt/browser' {
-  export const browser: import('webextension-polyfill').Browser;
+  export { browser, Browser } from '@wxt-dev/browser';
 }
 
 declare module 'virtual:wxt-plugins' {
diff --git a/packages/wxt/typedoc.json b/packages/wxt/typedoc.json
index d9edaddf..fa919313 100644
--- a/packages/wxt/typedoc.json
+++ b/packages/wxt/typedoc.json
@@ -3,8 +3,7 @@
     "src/client/index.ts",
     "src/testing/index.ts",
     "src/sandbox/index.ts",
-    "src/browser/index.ts",
-    "src/browser/chrome.ts",
+    "src/browser.ts",
     "src/index.ts",
     "src/modules.ts",
     "src/storage.ts"
diff --git a/packages/wxt/vitest.config.ts b/packages/wxt/vitest.config.ts
index 8bb1d0da..0c25b962 100644
--- a/packages/wxt/vitest.config.ts
+++ b/packages/wxt/vitest.config.ts
@@ -11,6 +11,7 @@ export default defineConfig({
       include: ['src/**'],
       exclude: ['**/dist', '**/__tests__', 'src/utils/testing'],
     },
+    setupFiles: ['./vitest.setup.ts'],
     globalSetup: ['./vitest.globalSetup.ts'],
   },
   server: {
@@ -22,7 +23,6 @@ export default defineConfig({
   resolve: {
     alias: {
       'wxt/testing': path.resolve('src/testing'),
-      'webextension-polyfill': path.resolve('src/virtual/mock-browser'),
     },
   },
 });
diff --git a/packages/wxt/vitest.setup.ts b/packages/wxt/vitest.setup.ts
new file mode 100644
index 00000000..a828762f
--- /dev/null
+++ b/packages/wxt/vitest.setup.ts
@@ -0,0 +1,5 @@
+import { fakeBrowser } from '@webext-core/fake-browser';
+import { vi } from 'vitest';
+
+vi.stubGlobal('chrome', fakeBrowser);
+vi.stubGlobal('browser', fakeBrowser);
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d461ccb5..ce82ef83 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -57,9 +57,6 @@ catalogs:
     '@types/ua-parser-js':
       specifier: ^0.7.39
       version: 0.7.39
-    '@types/webextension-polyfill':
-      specifier: ^0.12.1
-      version: 0.12.1
     '@vitejs/plugin-react':
       specifier: ^4.3.4
       version: 4.3.4
@@ -297,9 +294,6 @@ catalogs:
     web-ext-run:
       specifier: ^0.2.1
       version: 0.2.1
-    webextension-polyfill:
-      specifier: ^0.12.0
-      version: 0.12.0
 
 patchedDependencies:
   markdown-it-footnote:
@@ -698,12 +692,6 @@ importers:
       '@aklinker1/rollup-plugin-visualizer':
         specifier: 'catalog:'
         version: 5.12.0(rollup@4.34.9)
-      '@types/chrome':
-        specifier: 'catalog:'
-        version: 0.0.280
-      '@types/webextension-polyfill':
-        specifier: 'catalog:'
-        version: 0.12.1
       '@webext-core/fake-browser':
         specifier: 'catalog:'
         version: 1.3.1
@@ -713,6 +701,9 @@ importers:
       '@webext-core/match-patterns':
         specifier: 'catalog:'
         version: 1.0.3
+      '@wxt-dev/browser':
+        specifier: workspace:*
+        version: link:../browser
       '@wxt-dev/storage':
         specifier: workspace:^1.0.0
         version: link:../storage
@@ -833,9 +824,6 @@ importers:
       web-ext-run:
         specifier: 'catalog:'
         version: 0.2.1
-      webextension-polyfill:
-        specifier: 'catalog:'
-        version: 0.12.0
     devDependencies:
       '@aklinker1/check':
         specifier: 'catalog:'
@@ -2324,9 +2312,6 @@ packages:
   '@types/web-bluetooth@0.0.20':
     resolution: {integrity: sha512-g9gZnnXVq7gM7v3tJCWV/qw7w+KeOlSHAhgF9RytFyifW6AF61hdT2ucrYhPq9hLs5JIryeupHV3qGk95dH9ow==}
 
-  '@types/webextension-polyfill@0.12.1':
-    resolution: {integrity: sha512-xPTFWwQ8BxPevPF2IKsf4hpZNss4LxaOLZXypQH4E63BDLmcwX/RMGdI4tB4VO4Nb6xDBH3F/p4gz4wvof1o9w==}
-
   '@types/yauzl@2.10.3':
     resolution: {integrity: sha512-oJoftv0LSuaDZE3Le4DbKX+KS9G36NzOeSap90UIK0yMA/NhKJhqlSGtNDORNRaIbQfzjXDrQa0ytJ6mNRGz/Q==}
 
@@ -5365,9 +5350,6 @@ packages:
     resolution: {integrity: sha512-5D11VcjdGkA1/xax5UWL0YeAbDySKHzWFe6EpsoPNUMw5Uk9tKk9p6GUOfcaI5N7sINKfBMZYNsTBiu5dzJB9A==}
     engines: {node: '>=18.0.0', npm: '>=8.0.0'}
 
-  webextension-polyfill@0.12.0:
-    resolution: {integrity: sha512-97TBmpoWJEE+3nFBQ4VocyCdLKfw54rFaJ6EVQYLBCXqCIpLSZkwGgASpv4oPt9gdKCJ80RJlcmNzNn008Ag6Q==}
-
   webidl-conversions@7.0.0:
     resolution: {integrity: sha512-VwddBukDzu71offAQR975unBIGqfKZpM+8ZX6ySk8nYhVoo5CYaZyzt3YBvYtRtO+aoGlqxPg/B87NGVZ/fu6g==}
     engines: {node: '>=12'}
@@ -6664,8 +6646,6 @@ snapshots:
 
   '@types/web-bluetooth@0.0.20': {}
 
-  '@types/webextension-polyfill@0.12.1': {}
-
   '@types/yauzl@2.10.3':
     dependencies:
       '@types/node': 20.17.6
@@ -10092,8 +10072,6 @@ snapshots:
       - supports-color
       - utf-8-validate
 
-  webextension-polyfill@0.12.0: {}
-
   webidl-conversions@7.0.0: {}
 
   webpack-sources@3.2.3:
diff --git a/templates/react/wxt.config.ts b/templates/react/wxt.config.ts
index d1e35387..429f2b90 100644
--- a/templates/react/wxt.config.ts
+++ b/templates/react/wxt.config.ts
@@ -2,6 +2,5 @@ import { defineConfig } from 'wxt';
 
 // See https://wxt.dev/api/config.html
 export default defineConfig({
-  extensionApi: 'chrome',
   modules: ['@wxt-dev/module-react'],
 });
diff --git a/templates/solid/wxt.config.ts b/templates/solid/wxt.config.ts
index 0a5a994f..1cc7596d 100644
--- a/templates/solid/wxt.config.ts
+++ b/templates/solid/wxt.config.ts
@@ -2,6 +2,5 @@ import { defineConfig } from 'wxt';
 
 // See https://wxt.dev/api/config.html
 export default defineConfig({
-  extensionApi: 'chrome',
   modules: ['@wxt-dev/module-solid'],
 });
diff --git a/templates/svelte/wxt.config.ts b/templates/svelte/wxt.config.ts
index f0e4f9aa..5749b4e6 100644
--- a/templates/svelte/wxt.config.ts
+++ b/templates/svelte/wxt.config.ts
@@ -3,6 +3,5 @@ import { defineConfig } from 'wxt';
 // See https://wxt.dev/api/config.html
 export default defineConfig({
   srcDir: 'src',
-  extensionApi: 'chrome',
   modules: ['@wxt-dev/module-svelte'],
 });
diff --git a/templates/vanilla/wxt.config.ts b/templates/vanilla/wxt.config.ts
index 35c7ade7..1e2f53d3 100644
--- a/templates/vanilla/wxt.config.ts
+++ b/templates/vanilla/wxt.config.ts
@@ -1,6 +1,4 @@
 import { defineConfig } from 'wxt';
 
 // See https://wxt.dev/api/config.html
-export default defineConfig({
-  extensionApi: 'chrome',
-});
+export default defineConfig({});
diff --git a/templates/vue/wxt.config.ts b/templates/vue/wxt.config.ts
index 2ab714b1..55fbc4af 100644
--- a/templates/vue/wxt.config.ts
+++ b/templates/vue/wxt.config.ts
@@ -2,6 +2,5 @@ import { defineConfig } from 'wxt';
 
 // See https://wxt.dev/api/config.html
 export default defineConfig({
-  extensionApi: 'chrome',
   modules: ['@wxt-dev/module-vue'],
 });