shalanah
InAppSpy 🔎
inapp-spy helps developers detect when a website is opened inside an in-app browser (e.g. Instagram, Facebook, TikTok, Telegram).
It’s a maintained and refactored alternative to detect-inapp, with TypeScript support and regular updates – and it powers inappdebugger.com — a live testing tool for in-app browser detection.
Installation
npm install inapp-spyOr via CDN
<script src="https://cdn.jsdelivr.net/npm/inapp-spy@latest/dist/index.global.min.js"></script>Code Examples
Basic
import InAppSpy from "inapp-spy";
const { isInApp, appKey, appName } = InAppSpy();API Reference
Return Properties
isInApp
True if in-app browser has been detected
appKey
Machine-friendly key (use for logic)
facebookgsainstagramlinelinkedinsnapchattelegramthreadstiktoktwitterwechatmessenger
Can be undefined if isInApp is true.
appName
Human-readable name (e.g. "TikTok")
ua
Resolved or provided user agent string.
skipped
True if detection was bypassed via skip.
Optional Parameters
InAppSpy({
// Provide a UA string (server-side detection). Leave blank on client for better accuracy.
ua?: string;
// Exclude certain apps or platforms from detection.
skip?: {
appKey: AppKey;
platform?: "apple" | "android";
}[];
})SFSafariViewController Detection (Experimental)
Detect when a page is opened inside SFSafariViewController (helps with issues like awkward download UX).
⚠️ SFSVCExperimental may return false positives (e.g. Safari itself) and could change with future iOS updates. Always test on real devices.
💡 Tip: If you use escape links, add a query string — if present, skip detection to avoid false positives.
Usage
JavaScript
import InAppSpy, { SFSVCExperimental } from "inapp-spy";
const { isInApp } = InAppSpy(); // normal detection
// Detects in Safari 17+ - requires async
SFSVCExperimental().then((isSFSVC) => {
/* ... */
});React
import InAppSpy, { SFSVCExperimental } from "inapp-spy";
export const App = () => {
const [{ isInApp }] = useState(() => InAppSpy());
const [isSFSVC, setIsSFSVC] = useState(false);
useEffect(() => {
// Detects in Safari 17+ - requires async
SFSVCExperimental().then(setIsSFSVC);
}, []);
...
};Debugging Options
If detection fails on your app (but not on InAppDebugger), try adjusting options:
SFSVCExperimental({
debug?: boolean; // log details (default: false)
maxTime?: number; // ms before assuming Safari (default: 300)
maxVersion?: string; // e.g. "21.5.1" (default: none)
});License
Related
- InAppDebugger - Debug in-app browsers. Uses both
bowserandinapp-spylibraries. - Bowser - Browser + OS detection