1# Cloudflare Realtime SFU Reference
2 
3Expert guidance for building real-time audio/video/data applications using Cloudflare Realtime SFU (Selective Forwarding Unit).
4 
5## Reading Order
6 
7| Task | Files | ~Tokens |
8|------|-------|---------|
9| New project | README → configuration | ~1200 |
10| Implement publish/subscribe | README → api | ~1600 |
11| Add PartyTracks | patterns (PartyTracks section) | ~800 |
12| Build presence system | patterns (DO section) | ~800 |
13| Debug connection issues | gotchas | ~700 |
14| Scale to millions | patterns (Cascading section) | ~600 |
15| Add simulcast | patterns (Advanced section) | ~500 |
16| Configure TURN | configuration (TURN section) | ~400 |
17 
18## In This Reference
19 
20- **[configuration.md](configuration.md)** - Setup, deployment, environment variables, Wrangler config
21- **[api.md](api.md)** - Sessions, tracks, endpoints, request/response patterns
22- **[patterns.md](patterns.md)** - Architecture patterns, use cases, integration examples
23- **[gotchas.md](gotchas.md)** - Common issues, debugging, performance, security
24 
25## Quick Start
26 
27Cloudflare Realtime SFU: WebRTC infrastructure on global network (310+ cities). Anycast routing, no regional constraints, pub/sub model.
28 
29**Core concepts:**
30- **Sessions:** WebRTC PeerConnection to Cloudflare edge
31- **Tracks:** Audio/video/data channels you publish or subscribe to
32- **No rooms:** Build presence layer yourself via track sharing (see patterns.md)
33 
34**Mental model:** Your client establishes one WebRTC session, publishes tracks (audio/video), shares track IDs via your backend, others subscribe to your tracks using track IDs + your session ID.
35 
36## Choose Your Approach
37 
38| Approach | When to Use | Complexity |
39|----------|-------------|------------|
40| **PartyTracks** | Production apps with device switching, React | Low - Observable-based, handles reconnections |
41| **Raw API** | Custom requirements, non-browser, learning | Medium - Full control, manual WebRTC lifecycle |
42| **RealtimeKit** | End-to-end SDK with UI components | Lowest - Managed state, React hooks |
43 
44**Recommendation:** Start with PartyTracks for most production applications. See patterns.md for PartyTracks examples.
45 
46## SFU vs RealtimeKit
47 
48- **Realtime SFU:** WebRTC infrastructure (this reference). Build your own signaling, presence, UI.
49- **RealtimeKit:** SDK layer on top of SFU. Includes React hooks, state management, UI components. Part of Cloudflare AI platform.
50 
51Use SFU directly when you need custom signaling or non-React framework. Use RealtimeKit for faster development with React.
52 
53## Setup
54 
55Dashboard: https://dash.cloudflare.com/?to=/:account/calls
56 
57Get `CALLS_APP_ID` and `CALLS_APP_SECRET` from dashboard, then see configuration.md for deployment.
58 
59## See Also
60 
61- [Orange Meets Demo](https://demo.orange.cloudflare.dev/)
62- [Orange Source](https://github.com/cloudflare/orange)
63- [Calls Examples](https://github.com/cloudflare/calls-examples)
64- [API Reference](https://developers.cloudflare.com/api/resources/calls/)
65- [RealtimeKit Docs](https://developers.cloudflare.com/workers-ai/realtimekit/)
66