A nostr relay in C with sqlite on the back end.

NIPs

• NIP-01: Basic protocol flow implementation
• NIP-09: Event deletion
• NIP-11: Relay information document
• NIP-13: Proof of Work
• NIP-15: End of Stored Events Notice
• NIP-20: Command Results
• NIP-22: Event created_at Limits
• NIP-25: Reactions
• NIP-26: Delegated Event Signing
• NIP-28: Public Chat
• NIP-33: Parameterized Replaceable Events
• NIP-40: Expiration Timestamp
• NIP-42: Authentication of clients to relays
• NIP-45: Counting results. experimental
• NIP-50: Keywords filter. experimental
• NIP-70: Protected Events

NIP-13: Proof of Work Configuration

The relay supports NIP-13 Proof of Work validation with configurable settings. PoW validation helps prevent spam and ensures computational commitment from event publishers.

Environment Variables

Configure PoW validation using these environment variables:

• RELAY_POW_ENABLED - Enable/disable PoW validation (default: 1)

  • 1, true, or yes to enable
  • 0, false, or no to disable

• RELAY_MIN_POW_DIFFICULTY - Minimum required difficulty (default: 0)

  • Range: 0-64 (reasonable bounds)
  • 0 = no minimum requirement (events without PoW are accepted)
  • Higher values require more computational work

• RELAY_POW_MODE - Validation mode (default: basic)

  • basic - Basic PoW validation
  • full - Full validation with nonce tag requirements
  • strict - Strict anti-spam mode with committed target validation
  • disabled - Disable PoW validation entirely

Examples

# Basic setup - accept events with or without PoW
export RELAY_POW_ENABLED=1
export RELAY_MIN_POW_DIFFICULTY=0
export RELAY_POW_MODE=basic

# Anti-spam setup - require minimum difficulty 16
export RELAY_POW_ENABLED=1
export RELAY_MIN_POW_DIFFICULTY=16
export RELAY_POW_MODE=strict

# Disable PoW validation completely
export RELAY_POW_ENABLED=0

Behavior

• min_difficulty=0: Events without PoW are accepted; events with PoW are validated
• min_difficulty>0: All events must have valid PoW meeting minimum difficulty
• strict mode: Additional validation prevents difficulty commitment gaming
• NIP-11 integration: PoW configuration is advertised via relay information document

Testing

Run the comprehensive PoW test suite:

./tests/13_nip_test.sh

The test suite validates:

• NIP-11 PoW support advertisement
• Event acceptance without PoW (when min_difficulty=0)
• Event validation with valid PoW
• Configuration via environment variables
• NIP-13 reference event validation