archy/docs/adr/003-nostr-for-discovery.md

ADR-003: Nostr Relays for Node and App Discovery

Status: Accepted Date: 2026-03

Context

Archipelago nodes need to discover peers and community apps without a central registry. Options: custom P2P protocol, DHT, BitTorrent tracker, Nostr relays, IPFS.

Decision

Use Nostr relays (NIP-78, kind 30078) for both node discovery and marketplace app manifests.

Consequences

Positive

• Decentralized: Multiple independent relays; no single point of failure
• Existing infrastructure: Thousands of Nostr relays already running globally
• Censorship-resistant: If one relay censors, others still serve events
• Simple protocol: WebSocket + JSON — easy to implement without heavy dependencies
• Key management: Nostr uses secp256k1, same curve as Bitcoin — natural fit
• NIP-33 replaceable events: Latest event replaces previous — clean update model
• Tor-compatible: WebSocket over Tor SOCKS proxy works natively

Negative

• Relay availability varies: Some relays may be down or rate-limited
• No guaranteed persistence: Relays may prune old events
• Spam potential: Open publishing means anyone can publish junk manifests
• Latency: Querying multiple relays adds latency to discovery

Mitigation

• Query multiple relays in parallel; deduplicate results
• Cache results locally with 15-minute TTL
• Use trust scoring to rank manifests (DID verification, relay consensus, federation trust)
• Use hashtag filtering (archipelago-marketplace) to narrow queries