Bolt Rendezvous

Canonical Rust rendezvous server for the Bolt Protocol ecosystem.

What This Is

A lightweight WebSocket server that handles peer discovery and signal routing for Bolt-based applications. The rendezvous server is infrastructure, not a product.

Role in the Ecosystem

• Routes opaque signaling payloads between peers.
• Groups peers into rooms based on IP heuristics (RFC 1918, CGNAT, link-local).
• Provides presence notifications (join, leave, peer list).

Signaling only. The rendezvous server handles coordination metadata (SDP offers/answers, ICE candidates, hello/ack). File payload bytes never transit the rendezvous server — all payload data flows directly between peers over WebRTC DataChannel (P2P).

The rendezvous server is untrusted. It cannot observe file contents, encryption keys, or transfer metadata. All security guarantees come from Bolt-layer encryption.

Run Locally

# From source
cargo run --release

# With explicit host/port
cargo run --release -- --host 127.0.0.1 --port 4000

# With environment variables
BOLT_SIGNAL_HOST=127.0.0.1 BOLT_SIGNAL_PORT=4000 cargo run --release

The server listens on 0.0.0.0:3001 by default.

Run with Docker

# Build
docker build -t bolt-rendezvous .

# Run (default: 0.0.0.0:3001)
docker run -p 3001:3001 bolt-rendezvous

# Run with internet profile
docker run -p 3001:3001 -e BOLT_SIGNAL_PROFILE=internet bolt-rendezvous

# Override host/port
docker run -p 4000:4000 \
  -e BOLT_SIGNAL_HOST=0.0.0.0 \
  -e BOLT_SIGNAL_PORT=4000 \
  bolt-rendezvous

Deploy (Fly.io / VPS)

For public deployment, use the internet profile:

# Fly.io
fly launch --image bolt-rendezvous:latest
fly secrets set BOLT_SIGNAL_PROFILE=internet

# VPS (systemd, Docker, etc.)
docker run -d --restart=unless-stopped \
  -p 3001:3001 \
  -e BOLT_SIGNAL_PROFILE=internet \
  --name bolt-rendezvous \
  bolt-rendezvous

TLS termination should be handled by a reverse proxy (Caddy, nginx, Fly.io proxy) — the server itself speaks plain WebSocket (ws://).

Configuration

Resolution Order

CLI arguments take highest priority, then environment variables, then profile defaults, then hardcoded defaults.

Source	Host	Port	Log Level
CLI (--host, --port)	Highest	Highest	—
Env (BOLT_SIGNAL_HOST/PORT)	High	High	—
RUST_LOG	—	—	Highest
Profile defaults	Fallback	Fallback	Fallback
Hardcoded	0.0.0.0	3001	info

Profiles (BOLT_SIGNAL_PROFILE)

Variable	Value	Log Default	Notes
(unset)	—	info	Same as local
BOLT_SIGNAL_PROFILE	local	info	LAN/dev — verbose logging
BOLT_SIGNAL_PROFILE	internet	warn	Public deployment — quieter

RUST_LOG always overrides the profile log level when explicitly set.

Trust Boundary Limits (all profiles)

These limits are enforced regardless of profile and cannot be overridden:

Limit	Value
Max WebSocket message	1 MiB
Max device name	256 bytes
Max peer code	16 bytes
Rate limit	50 msg/sec per connection
Rate limit close threshold	3 consecutive violations

Dependencies

None. Standalone Rust binary.

Bundled By

• localbolt — via git subtree (offline mode)
• localbolt-app — via git subtree (offline mode)

Not Bundled By

• localbolt-v3 — connects to hosted endpoint only

License

MIT