SpacetimeDB: The Unified Database and Server for Real‑Time Applications

SpacetimeDB is a revolutionary relational database system that combines the power of a traditional RDBMS with the flexibility of an application server, all in a single binary written in Rust. In the past, building real‑time applications—whether it’s a multiplayer game, a chat platform, or a collaborative editing tool—required assembling a complex stack: a database, one or more microservices, message queues, and orchestration layers such as Kubernetes or Docker containers. SpacetimeDB collapses that stack into one compact runtime that runs the database and executes your application logic directly inside the database itself.

At its core, SpacetimeDB introduces the concept of a module—a stored procedure written in Rust (with plans for C# and other languages). Modules are first‑class citizens: they can define tables, indexes, triggers, and even expose APIs that clients call. When a client connects to the database via one of the official SDKs (Rust, C#, TypeScript), it can invoke module functions as if calling a local function, but all state is persisted in the database’s write‑ahead log (WAL). This design removes the latency introduced by network hops between application servers and databases.

Why is this important? Real‑time workloads are dominated by low latency rather than bulk analytics. Games like BitCraft Online rely on instant updates to player position, inventory, and world state. SpacetimeDB keeps all of that data in memory for fast access while persisting it safely to disk via WAL so the system can recover quickly after a crash. Benchmarks show that SpacetimeDB processes millions of operations per second with sub‑millisecond latency, outperforming many smart‑contract platforms by orders of magnitude.

The architecture is intentionally minimalistic: there are no external dependencies such as Docker, Kubernetes, or even a separate web server. The spacetime CLI tool manages the binary lifecycle—installing via simple curl scripts on macOS/Linux, PowerShell on Windows, or Docker images for those who prefer containerization. Once installed, you start a node with spacetime start, deploy modules by uploading your compiled Rust crate, and connect clients using one of the SDKs.

Modules are written in safe Rust, which means they inherit Rust’s guarantees: memory safety, thread safety, and zero‑cost abstractions. A module can declare tables with typed columns, set up triggers that fire on insert/update/delete, and expose RPC endpoints. Because modules run inside the database process, there is no context switching or serialization overhead; the same runtime handles both data storage and business logic.

Security is baked in through permission schemas defined at the module level. You can restrict which users can read or write specific tables, enforce fine‑grained access control, and even encode complex authorization rules directly into your Rust code. The database’s authentication system integrates with OAuth2 or custom token providers, so you can authenticate clients in a manner that matches your existing infrastructure.

SpacetimeDB is open for community contributions under the Business Source License 1.1 (BSL‑1.1), which later converts to AGPL‑v3 with a linking exception after a few years. This ensures that improvements made by users can flow back into the ecosystem while giving companies the freedom to keep proprietary code closed.

Getting started is straightforward: install the CLI, start a node, write a module in Rust or C#, and connect using the SDK of your choice. The documentation covers each step in detail, with tutorials for game development, chat servers, and collaboration tools. Whether you’re building a new multiplayer game from scratch or refactoring an existing microservices architecture into a single binary, SpacetimeDB offers a clean, high‑performance alternative that eliminates operational overhead.

In summary, SpacetimeDB reimagines the database as an application platform: it removes the middle layer of servers, delivers sub‑millisecond latency for real‑time interactions, and lets developers write their entire stack in one language—Rust. By unifying storage and logic into a single, easy‑to‑deploy binary, SpacetimeDB empowers teams to ship faster, maintain fewer moving parts, and scale seamlessly as user counts grow.