Instant Games

Notifications Overview

Updated: Mar 3, 2026
Copy for LLM
Notifications are one of the most important tools
This section covers the three primary notification channels available to Instant Games developers, compares their strengths and use cases, and links to the detailed documentation for each.

Notification Channels

A2U (App-to-User) API

The A2U API lets you send notifications directly from your backend server to players who have opted in to receive them. These notifications appear as Facebook notifications on the player’s device and in their notification tray.
Best for:
  • Server-driven re-engagement campaigns
  • Targeted notifications based on player behavior or segmentation
  • Scheduled notifications (e.g., “Your energy is full,” “Daily reward available”)
  • Broad announcements to your player base
Key characteristics:
  • Sent from your server, not from within the game client
  • Requires player opt-in
  • Subject to rate limits and content policies
  • Supports templates for consistent messaging
  • Can target specific players or segments
Read the full A2U API guide

Game Updates via Messenger

Game Updates via Messenger (formerly known as Game Bots) let you set up an automated Messenger experience for your game. Through a Messenger bot, you can send personalized messages, rich cards, and interactive content directly to players in their Messenger inbox.
Best for:
  • Rich, interactive re-engagement messages with images and buttons
  • Conversational experiences (player can respond to the bot)
  • Personalized messages based on game state
  • Ongoing engagement beyond gameplay sessions
Key characteristics:
  • Messages are delivered through Messenger
  • Requires setting up a Messenger bot and Page
  • Must pass App Review for Messenger bot functionality
  • Important: Must use real Facebook accounts for testing (test accounts cannot receive bot messages)
  • Supports rich message templates with images, buttons, and quick replies
  • Subject to Messenger platform policies and rate limits
Read the full Game Updates via Messenger guide

Notification Service

The Notification Service provides a streamlined way to schedule and manage notifications through Facebook’s infrastructure. It offers a simpler integration path compared to the A2U API for common notification scenarios.
Best for:
  • Scheduled notifications at specific times
  • Standardized notification patterns
  • Games that want a simpler integration without building full server-side notification logic
Key characteristics:
  • Managed by Facebook’s notification infrastructure
  • Supports scheduling for future delivery
  • Covers common notification types out of the box
  • Simpler setup compared to building a full A2U integration
Read the full Notification Service guide

Comparison

FeatureA2U APIGame Updates (Messenger)Notification Service
Delivery channel
Facebook notifications
Messenger inbox
Facebook notifications
Sent from
Your backend server
Messenger bot
Facebook’s infrastructure
Rich content
Limited (text + optional image)
Yes (images, buttons, cards, quick replies)
Limited (text + optional image)
Player interaction
One-way (notification only)
Two-way (player can respond)
One-way (notification only)
Setup complexity
Moderate (server-side API integration)
Higher (Messenger bot, Page, App Review)
Lower (configuration-based)
Targeting
Manual (you decide who to notify)
Manual (you decide who to message)
Configurable
Scheduling
You manage scheduling on your server
You manage timing on your server
Built-in scheduling
Player opt-in
Required
Required (Messenger subscription)
Required
Rate limits
Yes (per-player and aggregate)
Yes (Messenger platform limits)
Yes

When to Use Which Channel

Use A2U API when:

  • You have a backend server that can make API calls to Facebook
  • You want full control over notification timing, targeting, and content
  • You are sending notifications based on server-side events (e.g., a friend completed a challenge, a tournament ended)
  • You want to send notifications to segments of your player base (e.g., players who have not played in 3 days)

Use Game Updates via Messenger when:

  • You want to create rich, interactive re-engagement experiences
  • You want a conversational relationship with your players (e.g., daily tips, story updates)
  • You are building a game that benefits from ongoing Messenger presence
  • You want to send media-rich messages with images, buttons, and card carousels

Use Notification Service when:

  • You want a simpler integration path for common notification scenarios
  • You are scheduling recurring notifications (e.g., daily reminders)
  • You do not have a complex server-side infrastructure and want to leverage Facebook’s notification management

Using Multiple Channels

Many successful games use more than one notification channel. For example:
  • A2U API for targeted, behavior-driven re-engagement (e.g., “Your friend just beat your score”)
  • Game Updates via Messenger for rich, interactive content (e.g., daily challenge with a preview image and “Play Now” button)
  • Notification Service for scheduled reminders (e.g., “Your daily reward is ready”)
When using multiple channels, be mindful of notification fatigue. Coordinate across channels to avoid overwhelming players with too many messages.

Next Steps