FCM Payload Builder
Visually build the full FCM HTTP v1 message JSON — notification, data, android, apns, and webpush blocks — then export as cURL, Node.js, or a Flutter receive handler.
{
"message": {}
}FAQ
What is the FCM HTTP v1 message format?
It's the JSON body Firebase's v1 Send API expects, wrapped as { "message": {...} }. It can include a token/topic/condition target, a notification block, a flat string-only data block, and platform-specific android/apns/webpush overrides.
Why must data payload values be strings?
FCM's data payload is delivered to the client as a flat map of strings — numbers, booleans, and objects must be serialized (e.g. JSON.stringify) before sending and parsed back out in your app.
Does this send the notification?
No — this only builds the JSON message body. Use the cURL/Node export with a real OAuth access token or Admin SDK credential, or use the Push Notification Tester to actually send.
What does apns-priority 5 vs 10 mean?
10 delivers immediately and wakes the device; 5 is throttled for power efficiency and can be delayed. Apple requires priority 5 for any notification with content-available but no alert/sound/badge.