Stream Chat API
Stream Chat provides a scalable in-app chat infrastructure API with REST for management and WebSocket for real-time message delivery, supporting channels, threads, reactions, user presence, and moderation — with SDKs for most platforms.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
HMAC-signed JWTs with user_id binding prevent token reuse across users. API secret must be kept server-side. Stream supports message retention and deletion policies for compliance. Moderation APIs support content filtering and user banning.
⚡ Reliability
Best When
An agent needs to send or receive messages in a user-facing chat interface, operate as a chat bot, or monitor and moderate chat activity in an application built on Stream Chat.
Avoid When
You are building pure backend messaging infrastructure with no user-facing chat UI — a message queue or event streaming service would be more appropriate.
Use Cases
- • Create and configure chat channels for users, then monitor new message events via webhook to trigger agent workflows
- • Send automated messages or bot replies into channels using the server-side API with a bot user token
- • Retrieve message history from a channel for analysis, summarization, or compliance archiving
- • Manage user moderation actions (mute, ban, shadow-ban) in response to content policy violations detected by an agent
- • Create and update user profiles, assign roles, and control channel membership as part of a user onboarding automation
Not For
- • Email or push notification delivery — Stream Chat handles in-app messaging only; separate notification services are needed for email or mobile push
- • Asynchronous task queuing or event streaming beyond chat message delivery
- • High-volume machine-to-machine data pipelines — Stream Chat is optimized for human chat UX, not high-throughput automated message buses
Interface
Authentication
Server-side operations use the API key + API secret pair for signing requests via HMAC-SHA256. User-facing client tokens are JWTs signed with the API secret, containing the user_id claim. Server-side SDKs handle token generation automatically. Tokens can include optional expiry for security.
Pricing
Free tier is production-ready for small applications. Pricing scales with monthly active users (MAUs) and message volume on paid plans.
Agent Metadata
Known Gotchas
- ⚠ User tokens must be generated server-side with the API secret — exposing the API secret in client code is a critical security flaw; agents providing tokens to frontend clients must generate them server-side
- ⚠ Channel type configuration (messaging, livestream, team, etc.) determines default permissions and message retention — choosing the wrong channel type silently applies unexpected moderation rules
- ⚠ Webhook delivery is at-most-once with no built-in retry — agents relying on webhooks for message processing must handle gaps by polling the REST API for missed events
- ⚠ Message search requires a full-text search index that must be enabled per channel type in the Stream dashboard — queries against non-indexed channels return empty results silently
- ⚠ Rate limits are enforced per application, not per user — a spike from one bot user counts against the app's global rate limit, affecting real user traffic
Alternatives
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Scores are editorial opinions as of 2026-03-07.