FCM & OneSignal Push Notification Tester
Upload your Firebase service account JSON, or paste a OneSignal App ID and REST API key, to send a test push. Credentials are used once per request and never stored on the server.
ABOUT
Notifi Check is a free tool for testing Firebase Cloud Messaging (FCM) and OneSignal push notifications without writing any code. Paste a device or web-push token, upload your Firebase service account JSON — or paste a OneSignal App ID, REST API key, and player ID — and send a real notification straight from the browser. Useful for confirming that a Firebase project, OneSignal app, token, or web-push configuration actually works before wiring it into an app.
WHY TEST DIRECTLY
Push notification bugs are hard to isolate inside a full app — is the token stale, is the service account or REST API key misconfigured, is the payload malformed, or is the push provider itself unreachable? Sending a notification directly, outside your app code, narrows that down in one request. The WEB_PUSH tab also supports a validate-only dry run, so you can check a payload is well-formed without actually delivering it.
HOW IT WORKS
Your Firebase service account JSON is read once from the upload for that single request, used to create a short-lived Firebase Admin instance, and discarded immediately after — it is never written to disk, logged, or stored server-side. Get a service account key from your Firebase project under Project Settings → Service Accounts → Generate new private key — see the step-by-step guide if you need help. For OneSignal, your App ID and REST API key are sent once per request directly to the OneSignal API and never stored — find both under Settings → Keys & IDs in your OneSignal dashboard, or see the OneSignal setup guide.
MORE GUIDES
Hitting an FCM error? Check the FCM error code reference for what each one means and how to fix it. Deciding between providers? See FCM vs OneSignal.