- Free tier: Unlimited channels, 100 max connections, 200,000 messages a day, support
- Pros: Send messages from your server and subscribe to them in real-time from any client (Android, iOS, JavaScript, etc.) at massive scale (Pub/Sub). Great documentation, intuitive client libraries, and a powerful dashboard for testing, debugging, and analytics. Libraries available for various languages.
- Free tier: 3,000,000 feed updates per month into flat feeds, aggregated feeds or notification feeds
- Pros: SDK Support for Python, Go, JavaScript, Ruby, PHP, Java, Scala and several frameworks (Rails, Django, Node, .NET, Laravel, etc), plenty of example apps including an open-source Android app, community and email support, data import/export, replication of data, machine learning and personalization of feed data.
- Limitations: updates are processed in low priority