Backends

db0 uses a pluggable backend system. Both backends implement the same Db0Backend interface, so you can switch between them without changing application code.

SQLite

Local-first. No network calls. Default for development.

import { createSqliteBackend } from "@db0-ai/backends-sqlite"

// in-memory (ephemeral)
const backend = await createSqliteBackend()

// file-persisted
const backend = await createSqliteBackend({ dbPath: "./agent.db" })

Uses sql.js — pure JavaScript, no native dependencies. Works in any Node.js environment.

Features:

Embeddings stored as Float32Array blobs
Full-text search via FTS5
External file modification detection (multi-process safe)
Zero configuration

PostgreSQL

Production-ready. Cross-device sync. Requires the pgvector extension.

import { createPostgresBackend } from "@db0-ai/backends-postgres"

const backend = await createPostgresBackend({
  connectionString: "postgresql://user:pass@host:5432/db",
})

Features:

Native vector operations via pgvector
Cross-device and multi-agent sync
Standard PostgreSQL backup and replication
Connection pooling compatible

Backend interface

Both backends implement Db0Backend with these methods:

Memory operations

Method	Description
`memoryWrite(entry)`	Write a memory entry
`memorySearch(opts)`	Vector search with filters
`memoryList(opts)`	List memories with filters
`memoryGet(id)`	Get a specific memory
`memoryDelete(id)`	Delete a memory
`memoryAddEdge(edge)`	Add a relationship edge
`memoryGetEdges(id)`	Get edges for a memory
`memoryDeleteEdge(id)`	Delete an edge

State operations

Method	Description
`stateCheckpoint(opts)`	Save a checkpoint
`stateRestore(id)`	Restore to a checkpoint
`stateList(opts)`	List checkpoints
`stateGetCheckpoint(id)`	Get a specific checkpoint

Log operations

Method	Description
`logAppend(entry)`	Append a log entry
`logQuery(opts)`	Query log entries

Meta KV store

Method	Description
`metaGet(key)`	Get a value
`metaSet(key, value)`	Set a value

Lifecycle

Method	Description
`close()`	Close the backend connection