PostgreSQL

Nibchat uses SQLite by default — no setup required. For teams that need a managed database or want to run multiple Nibchat instances against a shared store, PostgreSQL is supported as a drop-in replacement.

Enabling PostgreSQL

Set POSTGRESQL_DSN to your connection string:

environment:
  - POSTGRESQL_DSN=postgres://user:password@db:5432/nibchat

Nibchat detects the variable at startup, connects to PostgreSQL, and runs all table migrations automatically. Existing SQLite deployments are unaffected — removing the variable reverts to SQLite.

Schema migrations

All tables are created with CREATE TABLE IF NOT EXISTS on every startup, so migrations are always idempotent. No external migration tool is required.

Knowledge base vector search

When the pgvector extension is available, Nibchat stores knowledge base embeddings as a native vector(1536) column with an HNSW index, enabling fast approximate nearest-neighbour search directly in SQL.

-- Nibchat creates this automatically when pgvector is present
CREATE INDEX IF NOT EXISTS knowledge_chunks_embedding_idx
  ON knowledge_chunks USING hnsw (embedding vector_cosine_ops);

If pgvector is not installed, Nibchat falls back to in-memory cosine similarity automatically — no configuration change needed.

Installing pgvector

The easiest way is to use the official pgvector/pgvector Docker image:

services:
  db:
    image: pgvector/pgvector:pg16
    environment:
      POSTGRES_USER: nibchat
      POSTGRES_PASSWORD: secret
      POSTGRES_DB: nibchat
    volumes:
      - pg-data:/var/lib/postgresql/data

  nibchat:
    image: ghcr.io/nibchat-ai/nibchat:latest
    environment:
      - POSTGRESQL_DSN=postgres://nibchat:secret@db:5432/nibchat
    depends_on:
      - db

volumes:
  pg-data:

Migrating from SQLite

There is no automated migration tool. If you need to carry over existing data, use a tool like pgloader or export/import via JSON. For most teams starting fresh with PostgreSQL is the practical approach.

Environment variables

Variable	Description
POSTGRESQL_DSN	PostgreSQL connection string (e.g. postgres://user:pass@host:5432/db). When set, PostgreSQL is used instead of SQLite.