Stream Chat vs. Ably Realtime

Stream Chat is a messaging API and SDK suite for developers building in-app chat. Teams integrate it to ship production messaging in weeks instead of building and maintaining real-time infrastructure in-house. Client SDKs cover React, Swift, Android, Flutter, React Native, Angular, JavaScript, Unity, and Unreal, each with a UI kit you can customize or replace entirely. The backend runs on Go and RocksDB across 12 global edge locations, holding sub-40ms latency and 5M concurrent connections in a single channel behind a 99.999% uptime SLA.

Ably helps teams deliver resilient AI UX and high-performance live experiences that stay fast and in sync worldwide. We provide the global realtime layer for AI agents, chat, notifications, live dashboards, and collaboration - engineered to handle peak demand without self-managed infrastructure. Teams like HubSpot and Intercom use Ably to avoid the cost and complexity of building and operating realtime systems, while still getting predictable performance at serious scale, handling 2T+ API operations per month.