SpacetimeDB — Server and Database in One

Introduction

SpacetimeDB merges the database and application server into a single layer. Instead of writing a separate backend service that queries a database, developers write modules (stored procedures in Rust or C#) that execute inside SpacetimeDB itself, eliminating the network hop between server and data.

What SpacetimeDB Does

• Runs server-side logic as compiled WebAssembly modules inside the database engine
• Provides a relational data model with SQL-like table definitions and queries
• Automatically synchronizes state changes to connected clients in real time
• Supports client SDKs for Rust, C#, TypeScript, and Python
• Handles authentication, subscriptions, and connection management out of the box

Architecture Overview

SpacetimeDB is written in Rust and uses a custom relational storage engine. Application logic is compiled to WebAssembly and loaded as modules that run inside the database process. When a module updates a table, the change is automatically pushed to subscribed clients via a built-in sync protocol. This eliminates the traditional three-tier architecture in favor of a two-tier model.

Self-Hosting & Configuration

• Install the CLI via the official install script on macOS, Linux, or Windows
• Run a local standalone instance with a single command for development
• Deploy to production using the provided Docker image or systemd service file
• Configure storage backends, listen addresses, and log levels via environment variables
• Modules are published and versioned through the CLI with zero-downtime updates

Key Features

• Unified server and database eliminates API boilerplate
• WebAssembly module isolation provides security and portability
• Real-time client sync without manual WebSocket or polling code
• Write server logic in Rust or C# with full type safety
• Designed for latency-sensitive applications like multiplayer games

Comparison with Similar Tools

• Supabase — Postgres-based BaaS with REST/GraphQL APIs, but server logic lives outside the DB
• Firebase — Google managed real-time DB with proprietary lock-in and limited query power
• Convex — Reactive backend with TypeScript functions, but not self-hostable in the same way
• SurrealDB — Multi-model database with embedded functions, but different sync model
• PocketBase — Lightweight Go backend with SQLite, simpler but no WASM module system

FAQ

Q: What languages can I use to write SpacetimeDB modules? A: Rust and C# are the primary supported languages. TypeScript support is in development.

Q: Is SpacetimeDB suitable for non-game applications? A: Yes. While it was designed with multiplayer games in mind, it works for any real-time collaborative application, chat system, or IoT data pipeline.

Q: How does SpacetimeDB handle scaling? A: A single SpacetimeDB instance handles vertical scaling. Horizontal sharding and clustering features are on the roadmap for future releases.

Q: What is the license? A: SpacetimeDB uses the BSL 1.1 license, which converts to open source after four years. The client SDKs are Apache 2.0 / MIT.

Sources

• https://github.com/clockworklabs/SpacetimeDB
• https://spacetimedb.com/docs