eiab (Escape In-App Browser)

Detect in-app browsers and generate escape URLs to open the current page in an external browser.

Supported Apps

*Telegram Android has no UA signal; detected via runtime window.TelegramWebview (client-side only).

Also detects generic WebView patterns (iOS WKWebView without Safari token, Android wv marker) and 15+ additional in-app browsers (Naver, KakaoStory, Band, Electron, etc.).

Install

npm install eiab

Also supports bun, pnpm, and yarn. This library is ESM-only.

Quick start

Vanilla JS

import { attemptEscape } from "eiab";
attemptEscape();

React

import {  EscapeInAppBrowser,  EiabEscapeDialog,  EiabSuccess,  EiabFailed,} from "eiab/react";
export default function Layout({ children }) {  return (    <>      {/* Auto-escapes where possible; shows dialog where it can't */}      <EscapeInAppBrowser fallback={<EiabEscapeDialog />} />      <EiabSuccess>You're in a normal browser!</EiabSuccess>      <EiabFailed>Please open this page in Safari or Chrome.</EiabFailed>      {children}    </>  );}

API

Core (eiab)

• isInAppBrowser(userAgent?: string): boolean -- Returns true if the UA matches in-app browser patterns.
• getEscapeUrl(currentUrl?, userAgent?): string | null -- Returns a URL/scheme to escape the in-app browser, or null.
• attemptEscape(currentUrl?, userAgent?): void -- Convenience wrapper that redirects to the escape URL if detected.

React (eiab/react)

• EscapeInAppBrowser -- Attempts automatic escape on mount. Accepts an optional fallback prop rendered when automatic escape fails (e.g. Meta iOS apps — see notes below).
• EiabEscapeDialog -- Bottom-sheet dialog with "Open in browser", "Copy link", and dismiss actions. Relies on native anchor navigation from a user tap.
• EiabEscapeLink -- Inline tappable link (native <a href> to the scheme URL). Renders nothing when not in an in-app browser.
• useIsInAppBrowser(userAgent?) -- Returns null during SSR, boolean after hydration.
• useEscapeUrl(url?, userAgent?) -- Returns the escape URL or null.
• EiabSuccess / EiabFailed -- Conditional rendering based on in-app detection.

Escape Strategies

The KakaoTalk/LINE/Instagram rows use each app's own native "open externally" scheme, handled by the host app rather than by iOS — the most robust class of escape.

Meta iOS caveat

Meta's iOS in-app browsers (Instagram, Facebook, Messenger, Threads) are hardened WKWebViews that drop x-safari-* scheme redirects without user activation, and IG v417+ filters them even on tap. There is no purely-browser-based API that reliably opens Safari from these apps.

For Instagram specifically, eiab instead emits Instagram's own native deep link, instagram://extbrowser/?url=..., which the Instagram app (not the WebView) handles. This is the best-grounded option — it's the same class of native-exit scheme used for KakaoTalk/LINE — but treat it as best-effort, not guaranteed: Meta's handler gates to trusted callers and may sanitize the URL back into the in-app browser, and there is no confirmed real-device proof it ejects to Safari on current iOS. Always pair it with the manual fallback below.

What to do:

1. Render EiabEscapeDialog (or EiabEscapeLink) so the scheme is triggered by a real user tap — native anchor navigation carries the strongest signal.
2. Offer the dialog's Copy link action and Meta's documented manual path, which is the only guaranteed exit: Instagram: tap ••• → Open in external browser. Facebook: tap the options menu → Open in external browser.

Notes

• eiab is intentionally small and dependency-free at runtime.