phoenixdb library

PhoenixDB — an ACID-compliant embedded key/value database for Dart.

The storage engine is written in Rust (B+Tree index, MVCC transactions, write-ahead log, CRC32-checksummed 4 KiB pages) and reached through a zero-overhead dart:ffi binding.

Synchronous use

final db = PhoenixDatabase.open('data.pdb');
db.insert(utf8Key('hello'), utf8Value('world'));
print(db.get(utf8Key('hello')));
db.close();

Asynchronous use (recommended in Flutter)

AsyncPhoenixDB runs every operation on a worker isolate so disk I/O never blocks the UI thread:

final db = await AsyncPhoenixDB.open('data.pdb');
await db.transaction((txn) async {
  await db.insert(utf8Key('a'), utf8Value('1'), txnId: txn);
  await db.insert(utf8Key('b'), utf8Value('2'), txnId: txn);
});
await db.close();

Vector search

PhoenixDB also ships an embedded k-NN index (HNSW over memory-mapped f32 vectors) for local-first semantic search:

final index = await AsyncPhoenixVectorDB.open('vectors.pvec', dimensions: 384);
await index.insert('doc-1', embedding);
final hits = await index.search(VectorQuery(query, k: 5));
print(hits.first.id);
await index.close();

Limits

Keys are capped at 1 MiB and values at 10 MiB by the FFI layer; the B+Tree additionally caps keys at 1 KiB so a node always holds at least two entries. Values larger than 1 KiB spill onto overflow pages transparently. Vectors are capped at 65 536 dimensions and their ids at 128 bytes.