NIP Support

Event Classification

Event Type	Kind Range	store.add() Behavior
Regular	1-9999 (excluding below)	Stored as-is
Replaceable	0, 3, 10000-19999	Only latest by (pubkey, kind) kept
Addressable	30000-39999	Only latest by (kind, pubkey, d-tag) kept
Ephemeral	20000-29999	Rejected (not stored)

Supported NIPs

NIP	Feature	Implementation
NIP-01	Event kinds, filters, tag queries	nip-rules.ts, filter-matcher.ts
NIP-01	Replaceable events (kind 0, 3, 10000-19999)	store.add() step 5
NIP-01	Addressable events (kind 30000-39999)	store.add() step 6, d-tag "" fallback
NIP-09	Event deletion (kind 5)	store.add() step 4, e-tag + a-tag
NIP-09	Pubkey verification on deletion	Author match required
NIP-09	Pending deletions (out-of-order arrival)	pendingDeletions Map with TTL
NIP-33	Parameterized replaceable events	Merged into NIP-01 addressable handling
NIP-40	Event expiration	isExpired() check on add + query

Replacement Rules

When a new event arrives for the same replaceable/addressable key:

1. Compare created_at — higher wins
2. Tiebreaker: lower event id (lexicographic) wins
3. Loser is discarded (not stored)

Deletion Flow

Online (during subscription)

kind:5 arrives → extract e-tags and a-tags
  → For each e-tag: find target in store, verify pubkey match → mark deleted
  → For each a-tag: find addressable event, verify pubkey + created_at → mark deleted
  → Target not found → register in pendingDeletions (TTL: 5min, max: 10000)

Pending (target arrives later)

Regular event arrives → check pendingDeletions
  → Match found + pubkey verified → mark deleted immediately
  → No match → store normally

Startup Reconciliation

connectStore(rxNostr, store, { reconcileDeletions: true });
// Fetches kind:5 events for all cached event IDs (chunked by 50)

Tag Indexing

All single-letter tags are indexed by default (NIP-01 compliant). Restrict with:

createEventStore({
  backend: memoryBackend(),
  indexedTags: ['e', 'p', 't', 'a', 'k'], // only these tags
});