vectlite

Embedded vector store for local-first AI applications.

vectlite is a single-file, zero-dependency vector database written in Rust with Node.js bindings. It gives you dense + sparse hybrid search, HNSW indexing, metadata filtering, transactions, and crash-safe persistence in a single .vdb file -- no server, no Docker, no network calls.

Installation

npm install vectlite

Requires Node.js 18+. Pre-built binaries are available for macOS (x86_64, arm64), Linux (x86_64), and Windows (x86_64). Other platforms fall back to compiling from source (requires Rust/Cargo).

Quick Start

const vectlite = require('vectlite')

// Create or open a database
const db = vectlite.open('knowledge.vdb', { dimension: 384 })

// Insert records with vectors, metadata, and sparse terms
db.upsert('doc1', embedding, { source: 'blog', title: 'Auth Guide' })
db.upsert('doc2', embedding2, { source: 'notes', title: 'Billing' })

// Search with filters
const results = db.search(embeddingQuery, { k: 5, filter: { source: 'blog' } })

// Clean up
db.compact()

Features

Core

• Single-file storage -- one .vdb file per database, portable and easy to back up
• Dense vectors -- cosine similarity with automatic HNSW indexing for large collections
• Sparse vectors -- BM25-scored inverted index for keyword retrieval
• Hybrid search -- dense + sparse fusion with linear or RRF strategies
• Rich metadata -- string, number, boolean, null, array, and nested object values
• Crash-safe WAL -- writes land in a write-ahead log first, then checkpoint with compact()
• Transactions -- atomic batched writes with db.transaction()
• File locking -- advisory locks prevent corruption from concurrent access

Search & Retrieval

• Metadata filters -- MongoDB-style operators: $eq, $ne, $gt, $gte, $lt, $lte, $in, $nin, $contains, $exists, $and, $or, $not
• Nested filters -- dot-path traversal (author.name), $elemMatch, $size on arrays and objects
• Named vectors -- multiple vector spaces per record (vectors: { title: [...], body: [...] })
• Multi-vector queries -- weighted search across vector spaces in a single call
• MMR diversification -- mmrLambda controls relevance vs. diversity trade-off
• Namespaces -- logical isolation with per-namespace or cross-namespace search
• Observability -- searchWithStats() returns timings, BM25 term scores, ANN stats, and per-result explain payloads

Data Management

• Physical collections -- vectlite.openStore() manages a directory of independent databases
• Bulk ingestion -- bulkIngest() with deferred index rebuilds for fast imports
• Snapshots -- db.snapshot(path) creates a self-contained copy
• Backup / Restore -- db.backup(dir) and vectlite.restore(dir, path) for full roundtrips
• Read-only mode -- vectlite.open(path, { readOnly: true }) for safe concurrent readers

Usage

Hybrid Search

const vectlite = require('vectlite')

const db = vectlite.open('knowledge.vdb', { dimension: 384 })

// Upsert with dense + sparse vectors
db.upsert(
  'doc1',
  denseEmbedding,
  { source: 'docs', title: 'Auth Setup', text: 'How to configure SSO...' },
  { sparse: vectlite.sparseTerms('How to configure SSO authentication') },
)

// Hybrid search
const results = db.search(queryEmbedding, {
  k: 10,
  sparse: vectlite.sparseTerms('SSO authentication'),
  fusion: 'rrf',
  filter: { source: 'docs' },
  explain: true,
})

for (const result of results) {
  console.log(result.id, result.score)
}

Collections

const store = vectlite.openStore('./my_collections')
const products = store.createCollection('products', 384)
products.upsert('p1', embedding, { name: 'Widget', price: 9.99 })

const logs = store.openOrCreateCollection('logs', 128)
console.log(store.collections()) // ["logs", "products"]

Transactions

const tx = db.transaction()
try {
  tx.upsert('doc1', emb1, { source: 'a' })
  tx.upsert('doc2', emb2, { source: 'b' })
  tx.delete('old_doc')
  tx.commit() // All operations commit atomically
} catch (err) {
  tx.rollback() // Roll back on error
  throw err
}

Text Helpers

async function run() {
  // embedFn can be sync or async
  await vectlite.upsertText(db, 'doc1', 'Auth setup guide', embedFn, { source: 'docs' })
  const results = await vectlite.searchText(db, 'how to authenticate', embedFn, { k: 5 })
}

Snapshots & Backup

db.snapshot('/backups/knowledge_2024.vdb') // Self-contained copy
db.backup('/backups/full/')                // Full backup with ANN sidecars

const restored = vectlite.restore('/backups/full/', 'restored.vdb')

Read-Only Mode

const ro = vectlite.open('knowledge.vdb', { readOnly: true })
const results = ro.search(query, { k: 5 }) // Reads work
ro.upsert(...)                              // Throws VectLiteError

Search Diagnostics

const outcome = db.searchWithStats(query, {
  k: 5,
  sparse: terms,
  explain: true,
})

console.log(outcome.stats.timings)      // { dense_us: 120, sparse_us: 45, ... }
console.log(outcome.stats.used_ann)     // true
console.log(outcome.results[0].explain) // Detailed scoring breakdown

Filter Operators

How It Works

• Records are stored in a compact binary .vdb snapshot file
• Writes go through a crash-safe WAL (.wal) before being applied in memory
• compact() folds the WAL into the snapshot and persists HNSW sidecar files
• Dense search uses HNSW indexes (auto-built for collections above ~128 records)
• Sparse search uses an inverted index with BM25 scoring
• Hybrid fusion combines dense + sparse via linear combination or reciprocal rank fusion
• Advisory file locks (flock) prevent concurrent write corruption

Links

• Official Documentation
• GitHub Repository
• Issue Tracker
• PyPI Package

License

MIT