Introduction

Tether is a realtime SQLite database service that makes building reactive applications simple.

What is Tether?

Tether provides per-project SQLite databases with realtime subscriptions, type-safe functions, and SDKs for Vue/Nuxt, React, Svelte, and vanilla JavaScript.

Key features:

  • Per-project databases — Each project gets its own isolated SQLite database with WAL mode for optimal performance.
  • Realtime subscriptions — Subscribe to queries and receive instant updates when your data changes.
  • Type-safe functions — Define queries, mutations, and actions with full TypeScript support.
  • Framework SDKs — Official SDKs for Vue/Nuxt, React, Svelte, and vanilla JavaScript.
  • File storage — Upload and serve files via Cloudflare R2 with signed URLs for secure access.
  • Offline resilience — Automatic reconnection with change sync ensures no data is missed during disconnections.

Architecture

Tether uses a simple but powerful architecture:

  • Tether Server — Manages SQLite databases, function execution, and realtime connections
  • Tether CLI — Project scaffolding, schema migrations, and deployment
  • Tether SDK — Client libraries for your framework of choice
  • Tether Dashboard — Web UI for project management and data browsing

How it works

  1. Define your database schema using TypeScript
  2. Write queries, mutations, and actions as functions
  3. Connect from your app using the SDK
  4. Subscribe to data and get realtime updates