Negentropy

low level

Basic reconciliation

final filter = Filter(
  authors: ['your_pubkey'],
);

final response = ndk.nip77.reconcile(
  relayUrl: 'wss://relay.example.com',
  filter: filter,
);

// Wait for completion
final result = await response.future;
print('Sync complete: ${result.needIds.length} events to fetch, ${result.haveIds.length} events to broadcast');

Relay authentication (NIP-42)

Some relays only reconcile with a client that authenticated, the same way they only serve a request to one. The auth parameter says which identity the reconciliation may be attributed to, exactly like on requests:

final response = ndk.nip77.reconcile(
  relayUrl: 'wss://relay.example.com',
  filter: Filter(authors: [myPubkey]),
  auth: AuthPolicy.require(account),
);

policy	connection	what a relay learns
`AuthPolicy.never()`	anonymous, always	nothing. A relay that refuses the negotiation without an identity simply does not reconcile
`AuthPolicy.allow(a)`	anonymous, moves to one bound to `a` once the relay refuses	who you are, but only after that relay asked
`AuthPolicy.require(a)`	bound to `a` from the start	who you are, as soon as it sends a challenge

Without auth, a refused negotiation authenticates as the currently logged-in account, so the relay decides when your identity is revealed. Pass auth explicitly whenever that matters.

If require names an account that cannot sign, no connection can carry the reconciliation. Rather than fall back to the anonymous one, which is what require rules out, nothing is sent and reconcile itself throws Nip77AuthUnavailableException.

Error handling

Relay doesn't support NIP-77

try {
  final response = ndk.nip77.reconcile(
    relayUrl: 'wss://relay.example.com',
    filter: filter,
  );
  await response.future;
} on Nip77NotSupportedException catch (e) {
  print('Relay does not support NIP-77: ${e.message}');
  // Fall back to traditional query with paginate true
  ndk.requests.query(filter: filter, paginate: true);
} on Nip77TimeoutException catch (e) {
  print('Reconciliation timed out: ${e.timeout}');
}

Relay requires an identity you did not give it

try {
  await ndk.nip77.reconcile(
    relayUrl: 'wss://relay.example.com',
    filter: filter,
    auth: const AuthPolicy.never(),
  ).future;
} on Nip77AuthRequiredException catch (e) {
  print('Relay wants an identity: ${e.message}');
} on Nip77AuthUnavailableException catch (e) {
  print('${e.pubkey} cannot sign, nothing was sent');
}

When to use

✅ Good for:

Syncing large event sets (long history)
Periodic reconciliation with home relays
Ensuring relay has all your events
Discovering events you missed

❌ Use other methods for:

Small queries → use ndk.requests.query()