Push Notification Payload Builder
Build push notification JSON payloads for FCM (Firebase Cloud Messaging) v1 API, FCM Legacy API, and APNs (Apple Push Notification Service). Generate ready-to-use JSON with custom data, priority settings, and platform-specific fields.
How Does the Push Notification Payload Builder Work?
The Push Notification Payload Builder is a free browser-based tool that generates valid JSON payloads for sending push notifications via Firebase Cloud Messaging (FCM) or Apple Push Notification Service (APNs). Select your target platform, fill in your notification details, and instantly get a properly structured JSON payload ready to use in your API calls or testing tools.
Push notifications are a critical engagement channel for mobile apps, but crafting the correct JSON payload format can be tricky. Each platform has its own structure, required fields, and naming conventions. FCM v1 API uses a nested message object with platform-specific overrides for Android and iOS. The legacy FCM API uses a flatter structure with a "to" field for targeting. APNs requires a specific "aps" dictionary with alert, sound, and badge fields. Getting any of these wrong means your notifications silently fail with no feedback to the user.
Supported Platforms
FCM v1 API is Google's current recommended API for Firebase Cloud Messaging. It uses OAuth 2.0 authentication and supports platform-specific notification customization. The generated payload includes both Android-specific fields (like channel_id and priority) and APNs-specific fields (like sound and badge) in a single request, letting FCM handle delivery to both platforms.
FCM Legacy API is the older HTTP API that uses a server key for authentication. While Google recommends migrating to v1, many existing projects still use this format. The legacy payload is simpler and flatter, using a "to" field for topic targeting and a top-level "priority" field.
APNs (Apple) generates the JSON payload format required by Apple's Push Notification Service. This includes the required "aps" dictionary with alert title and body, sound configuration, badge count, and the mutable-content flag for notification service extensions. Custom data keys are placed at the top level alongside the "aps" dictionary.
Custom Data and Priority
All three platforms support custom key-value data that your app can read when the notification is received. Enter pairs in the format "key1=value1, key2=value2" and the builder will place them in the correct location for each platform. The priority setting controls whether the notification is delivered immediately (high) or batched for battery optimization (normal). High priority should be used for time-sensitive notifications like messages or alerts, while normal priority is appropriate for content updates and non-urgent information.
All processing happens entirely in your browser. Your notification content, server keys, and custom data never leave your device, making this tool safe to use with production payloads and sensitive data fields.