Powerful Features for Real-time Apps
Everything you need to build scalable, reliable real-time applications. From pub/sub messaging to presence tracking and beyond.
Real-time Pub/Sub Messaging
Topic-based publish-subscribe messaging built on WebSocket connections. Messages are delivered in milliseconds with automatic reconnection and message queuing.
- Topic-based routing with wildcards
- Automatic reconnection handling
- Message queuing for offline clients
- Binary and JSON message support
Presence Tracking
Know who's online in real-time. Track user presence across your entire application with automatic join/leave events.
- Real-time online/offline status
- Per-topic presence lists
- Custom presence metadata
- Presence change callbacks
Quality of Service (QoS)
Choose the right delivery guarantee for your use case. From fire-and-forget to exactly-once delivery.
- QoS 0: At-most-once (fire and forget)
- QoS 1: At-least-once (acknowledged)
- QoS 2: Exactly-once (transactional)
- Per-message QoS configuration
Access Scopes (Multi-Tenancy)
Partition communication by tenant using topic namespace scoping. Assign actors to scopes and all messages, webhooks, and state are automatically isolated.
- Topic namespace partitioning per tenant
- MQTT-level enforcement, no app code needed
- Scope metadata flows through webhooks
- Works across rooms, topics, and presence
Access Control (ACL)
Fine-grained permissions for every topic. Control who can publish, subscribe, and manage topics with role-based access.
- Per-topic read/write permissions
- Role-based access control
- Actor-level authentication
- API key scoping
Rooms & Namespaces
Organize your topics into logical rooms. Isolate conversations, games, or sessions with automatic namespace management.
- Logical topic grouping
- Room-level presence tracking
- Automatic cleanup on disconnect
- Cross-room messaging
Topic Filters
Narrow message delivery to specific entities within a topic. Subscribe to "bookings" with filters ["booking_1", "booking_2"] and only receive updates for those items. Swap filters dynamically without resubscribing.
- Filter by entity ID within a topic
- Dynamic filter management (set, add, remove)
- Infrastructure-level routing — no payload inspection
- Up to 100 filters per topic per connection
Webhooks
Configure webhooks per topic to integrate with external systems. Pre-populate state on subscribe and react to published messages with automatic tenant isolation via access scopes.
- Per-topic webhook configuration
- Automatic scope isolation in payloads
- Dead Letter Queue for failed requests
- Custom headers and authentication
Message Logging & Replay
Persist messages for debugging, auditing, and reliable delivery. Automatically replay missed messages when clients reconnect.
- Configurable per-topic logging
- Message history for debugging
- Automatic replay on reconnect
- Configurable retention periods
Lobbies
Observe presence across multiple rooms simultaneously. Perfect for dashboards, admin panels, and monitoring applications.
- Multi-room presence observation
- Dashboard and ops center views
- Real-time status aggregation
- Up to 10 lobbies per room
Task Handoff
Dispatch tasks to AI agents by capability tags. Built-in pooling, routing, and result collection for multi-agent workflows.
- Tag-based capability routing
- Worker pooling and load balancing
- Result collection and callbacks
- Timeout and retry policies
Blackboard State
Shared key-value state with versioning for multi-agent coordination. All agents see the same state with conflict-free updates.
- Shared key-value store
- Version tracking for conflict resolution
- Real-time state change notifications
- Scoped per-room isolation
Approval Gates
Human-in-the-loop gating for agent workflows. Pause agent execution until a human approves, rejects, or modifies the proposed action.
- Pause/resume agent workflows
- Approve, reject, or modify actions
- Timeout with configurable defaults
- Audit trail for compliance
Usage Analytics
Track connections, messages, and bandwidth in real-time. Monitor your application health with detailed usage metrics.
- Real-time connection metrics
- Daily message aggregates
- Bandwidth tracking
- Per-app usage breakdowns
MCP Server (Build with AI)
Connect Claude Desktop, Cursor, or any MCP-compatible AI assistant to manage your NoLag infrastructure. Create apps, actors, rooms, dispatch tasks, and query agent state - all from natural language.
- 47+ tools for full infrastructure management
- Scaffold agent workflows from a prompt
- Dispatch tasks and query state from your IDE
- Works with Claude Desktop, Cursor, and any MCP client
Built for Production
Production-grade infrastructure with the developer experience you deserve.
MessagePack Protocol
Efficient binary serialization for minimal bandwidth usage and fast parsing.
Multi-Region
Deploy closer to your users with edge locations worldwide.
Auto-Reconnection
Automatic reconnection with exponential backoff and message replay.
Analytics Dashboard
Real-time metrics, connection stats, and message throughput monitoring.
TypeScript First
Full TypeScript support with typed events and autocomplete.
Scalable Infrastructure
Built on Erlang/OTP for fault-tolerant, distributed messaging.
Technical Overview
The technical details that make NoLag fast, reliable, and developer-friendly.
Protocol Specifications
- Transport
- WebSocket (binary)
- Serialization
- MessagePack (not JSON)
- Max Message Size
- 256KB
- Heartbeat
- 30 seconds
- Reconnect Attempts
- Up to 10 with exponential backoff
Delivery Guarantees (QoS)
Fire-and-forget (fastest)
Guaranteed delivery, may duplicate (default)
Guaranteed single delivery (transactions)
Actor Types (Who Connects)
Device
Frontend clients
Example: Browser, mobile app
User
Authenticated users
Example: Logged-in account
Server
Backend services
Example: Your API server
Session
Temporary connections
Example: Anonymous guest
See it in action
Try our interactive playground or dive into the documentation.