diff --git a/src/browser/chromium.js b/src/browser/chromium.js
index f2d2c4d..351fc05 100644
--- a/src/browser/chromium.js
+++ b/src/browser/chromium.js
@@ -7,13 +7,15 @@ const presets = { // Presets from OpenAsar
   'memory': '--in-process-gpu --js-flags="--lite-mode --optimize_for_size --wasm_opt --wasm_lazy_compilation --wasm_lazy_validation --always_compact" --renderer-process-limit=2 --enable-features=QuickIntensiveWakeUpThrottlingAfterLoading' // Less (?) memory usage
 };
 
-export default async ({ browserPath, dataPath }, { url, windowSize, allowHTTP }, extra) => {
+export default async ({ browserPath, dataPath }, { url, windowSize, allowHTTP, extensions }, extra) => {
+  console.log(extensions);
+
   return await StartBrowser(browserPath, [
     `--app=${url}`,
-    `--remote-debugging-pipe`,
     `--user-data-dir=${dataPath}`,
     windowSize ? `--window-size=${windowSize.join(',')}` : '',
     ![true, 'mixed'].includes(allowHTTP) ? `--enable-strict-mixed-content-checking` : '--allow-running-insecure-content',
-    ...`--new-window --no-first-run --no-default-browser-check --disable-component-extensions-with-background-pages --disable-extensions --disable-default-apps --disable-breakpad --disable-crashpad --disable-background-networking --disable-domain-reliability --disable-component-update --disable-sync --disable-features=AutofillServerCommunication --in-process-gpu ${presets.perf}`.split(' ')
+    Array.isArray(extensions) && extensions.length > 0 ? `--load-extension=${(await Promise.all(extensions)).flat().join(',')}` : '',
+    ...`--new-window --no-first-run --no-default-browser-check --disable-component-extensions-with-background-pages --disable-default-apps --disable-breakpad --disable-crashpad --disable-background-networking --disable-domain-reliability --disable-component-update --disable-sync --disable-features=AutofillServerCommunication --in-process-gpu ${presets.perf}`.split(' ')
   ], 'stdio', extra);
 };
\ No newline at end of file
diff --git a/src/browser/firefox.js b/src/browser/firefox.js
index 12d5666..59d7db2 100644
--- a/src/browser/firefox.js
+++ b/src/browser/firefox.js
@@ -1,10 +1,11 @@
-import { mkdir, writeFile } from 'fs/promises';
-import { join } from 'path';
+import { mkdir, writeFile, copyFile, access } from 'fs/promises';
+import { join, basename } from 'path';
 
 import StartBrowser from '../launcher/start.js';
 
+const exists = path => access(path).then(() => true).catch(() => false);
 
-export default async ({ browserPath, dataPath }, { url, windowSize, allowHTTP }, extra) => {
+export default async ({ browserPath, dataPath }, { url, windowSize, allowHTTP, extensions }, extra) => {
   await mkdir(dataPath, { recursive: true });
   await writeFile(join(dataPath, 'user.js'), `
 user_pref("toolkit.legacyUserProfileCustomizations.stylesheets", true);
@@ -31,7 +32,7 @@ user_pref('security.mixed_content.upgrade_display_content', true);
 /* user_pref('privacy.window.maxInnerWidth', ${windowSize[0]});
 user_pref('privacy.window.maxInnerHeight', ${windowSize[1]}); */
 
-  await mkdir(join(dataPath, 'chrome'), { recursive: true });
+  await mkdir(join(dataPath, 'chrome'));
   await writeFile(join(dataPath, 'chrome', 'userChrome.css'), `
 .titlebar-spacer, #firefox-view-button, #alltabs-button, #tabbrowser-arrowscrollbox-periphery, .tab-close-button {
   display: none;
@@ -78,6 +79,12 @@ html:not([tabsintitlebar="true"]) .tab-icon-image {
 }
 `);
 
+  await mkdir(join(dataPath, 'extensions'));
+  for (const ext of (await Promise.all(extensions)).flat()) {
+    const installPath = join(dataPath, 'extensions', basename(ext));
+    if (!await exists(installPath)) await copyFile(ext, installPath);
+  }
+
   return await StartBrowser(browserPath, [
     ...(!windowSize ? [] : [ `-window-size`, windowSize.join(',') ]),
     `-profile`, dataPath,
diff --git a/src/extensions.js b/src/extensions.js
new file mode 100644
index 0000000..852d49b
--- /dev/null
+++ b/src/extensions.js
@@ -0,0 +1,24 @@
+export const _extensions = {
+  chromium: [],
+  firefox: []
+};
+
+const parseArgs = args => args.flatMap(x => typeof x === 'function' ? x() : x);
+
+export const add = (..._args) => {
+  const args = parseArgs(_args);
+
+  for (const ext of args) {
+    if (ext.chromium) _extensions.chromium.push(ext.chromium);
+    if (ext.firefox) _extensions.firefox.push(ext.firefox);
+  }
+};
+
+export const remove = (..._args) => {
+  const args = parseArgs(_args);
+
+  for (const ext of args) {
+    if (ext.chromium) _extensions.chromium.splice(_extensions.chromium.indexOf(ext.chromium), 1);
+    if (ext.firefox) _extensions.firefox.splice(_extensions.firefox.indexOf(ext.firefox), 1);
+  }
+};
\ No newline at end of file
diff --git a/src/index.js b/src/index.js
index 8ad18ac..d09bcd8 100644
--- a/src/index.js
+++ b/src/index.js
@@ -6,6 +6,7 @@ import { log } from './lib/logger.js';
 import Chromium from './browser/chromium.js';
 import Firefox from './browser/firefox.js';
 
+import * as ExtensionsAPI from './extensions.js';
 import LocalHTTP from './lib/local/http.js';
 
 process.versions.gluon = '0.13.0-alpha.0';
@@ -200,7 +201,8 @@ const startBrowser = async (url, { allowHTTP, windowSize, forceBrowser, forceEng
   }, {
     url: openingLocal ? localUrl : url,
     windowSize,
-    allowHTTP
+    allowHTTP,
+    extensions: ExtensionsAPI._extensions[browserType]
   }, {
     browserName: browserFriendlyName,
     url: openingLocal ? basePath : url,
@@ -232,11 +234,15 @@ export const open = async (url, opts = {}) => {
 
     Browser.page.eval(toRun);
 
-    await Browser.cdp.send(`Page.enable`);
     await Browser.cdp.send(`Page.addScriptToEvaluateOnNewDocument`, {
       source: toRun
     });
   }
 
   return Browser;
+};
+
+export const extensions = {
+  add: ExtensionsAPI.add,
+  remove: ExtensionsAPI.remove
 };
\ No newline at end of file