High-performance Nostr relay built with Rust and OpenSearch.

• NIP-01, NIP-09, NIP-11, NIP-16, NIP-33, NIP-45, NIP-50, NIP-86
• Multi-process architecture for connection scaling
• OpenSearch backend with full-text search
• Realtime streaming via Redis pub/sub (multi-node support)
• Advanced NIP-50 search extensions (top, hot, controversial, rising)
• Event counting via NIP-45 COUNT
• Relay management API (NIP-86) with NIP-98 authentication
• Relay-to-relay sync via Negentropy
• Prometheus metrics

# Start OpenSearch
docker run -d -p 9200:9200 \
  -e "discovery.type=single-node" \
  -e "OPENSEARCH_INITIAL_ADMIN_PASSWORD=Admin123!" \
  opensearchproject/opensearch:latest

# Build and run
cargo build --release
./target/release/umbra

Set via environment variables:

• UMBRA_BIND - WebSocket address (default: 0.0.0.0:7777)
• UMBRA_OPENSEARCH_URL - OpenSearch URL(s), comma-separated for multiple nodes (default: http://localhost:9200)
• UMBRA_REDIS_URL - Redis URL for cross-node streaming (optional, e.g., redis://localhost:6379)
• UMBRA_WORKERS - Worker processes (default: CPU cores)
• UMBRA_ADMIN_PUBKEYS - Comma-separated list of admin pubkeys for NIP-86
• UMBRA_RELAY_URL - Public relay URL for NIP-98 verification (default: http://localhost:7777)
• UMBRA_POOL_MAX_IDLE_PER_HOST - Max idle connections to OpenSearch per host (default: 100)
• UMBRA_POOL_IDLE_TIMEOUT_SECS - Idle connection timeout in seconds (default: 300)
• RUST_LOG - Log level (default: info)

Umbra supports realtime event streaming to connected clients. When a client sends a REQ message, Umbra returns matching stored events, sends EOSE, then keeps the subscription open for new events.

Local streaming works out of the box - events received by a node are immediately broadcast to matching local subscriptions using in-memory inverted indexes for efficient O(1) lookups by author, kind, and tags.

Cross-node streaming requires Redis. When configured, events are published to a nostr:events Redis pub/sub channel, allowing multiple Umbra nodes to share events in realtime:

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   Node A    │────▶│    Redis    │◀────│   Node B    │
│  (events)   │◀────│  pub/sub    │────▶│  (events)   │
└─────────────┘     └─────────────┘     └─────────────┘

Umbra supports powerful NIP-50 search extensions for content discovery:

{"kinds": [1], "search": "sort:hot bitcoin", "limit": 50}

Sort Modes:

• sort:top - Most referenced events (all-time best)
• sort:hot - Trending now (recent + popular)
• sort:controversial - Mixed positive/negative reactions
• sort:rising - Rapidly gaining traction

Prometheus metrics available at http://localhost:9090/metrics

Run the test suite:

# Run all tests (single-threaded for env var tests)
cargo test -- --test-threads=1

# Run clippy with pedantic checks
cargo clippy -- -D warnings -D clippy::all -D clippy::pedantic

Note: Some tests manipulate environment variables and require single-threaded execution to avoid race conditions.

AGPLv3