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<h3 align="center">
Development at the speed of light.
</h3>
</p>
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<br>
## What is SpacetimeDB?
SpacetimeDB is a relational database that is also a server. You upload your application logic directly into the database, and clients connect to it without any server in between. It is built for reactive applications, where every client sees changes as they happen: web apps like collaborative tools, dashboards, and chat, as well as multiplayer games.
Write your schema and business logic as a **module** in [Rust](https://spacetimedb.com/docs/quickstarts/rust), [C#](https://spacetimedb.com/docs/quickstarts/c-sharp), [TypeScript](https://spacetimedb.com/docs/quickstarts/typescript), or [C++](https://spacetimedb.com/docs/quickstarts/c-plus-plus). SpacetimeDB compiles it, runs it inside the database, and automatically synchronizes state to connected clients in real-time.
Instead of deploying a web or game server that sits in between your clients and your database, your clients connect directly to the database and execute your application logic in your module. You can write all of your permission and authorization logic right inside your module just as you would in a normal server.
This means that you can write your entire application in a single language and deploy it as a single binary. No more separate webserver, no more containers, no more Kubernetes, no more VMs, no more DevOps, no more caching later. Zero infrastructure to manage.
<figure>
<img src="./images/basic-architecture-diagram.png" alt="SpacetimeDB Architecture" style="width:100%">
<figcaption align="center">
<p align="center"><b>SpacetimeDB application architecture</b><br /><sup><sub>(elements in white are provided by SpacetimeDB)</sub></sup></p>
</figcaption>
</figure>
SpacetimeDB is optimized for maximum speed and minimum latency. SpacetimeDB provides all the ACID guarantees of a traditional RDBMS, with all the speed of an optimized web server. All application state is held in memory for fast access, while a commit log on disk provides [durability](#durability) and crash recovery. The entire backend of our MMORPG [BitCraft Online](https://bitcraftonline.com) runs as a single SpacetimeDB module: chat, items, terrain, player positions, everything, synchronized to thousands of players in real-time.
## Quick Start
### 1. Install
```bash
# macOS / Linux
curl -sSf https://install.spacetimedb.com | sh
# Windows (PowerShell)
iwr https://windows.spacetimedb.com -useb | iex
```
### 2. Log in
```bash
spacetime login
```
This opens a browser to authenticate with GitHub. Your identity is linked to your account so you can publish databases.
### 3. Start developing
```bash
spacetime dev --template chat-react-ts
```
That is it. This creates a project from a template, publishes it to [Maincloud](https://spacetimedb.com/docs/how-to/deploy/maincloud), and watches for file changes, automatically rebuilding and republishing on save. See [pricing](https://spacetimedb.com/pricing) for details.
## How It Works
SpacetimeDB modules define **tables** (your data) and **reducers** (your logic). Clients connect, call reducers, and subscribe to tables. When data changes, SpacetimeDB pushes updates to subscribed clients automatically.
```rust
// Define a table
#[spacetimedb::table(accessor = messages, public)]
pub struct Message {
#[primary_key]
#[auto_inc]
id: u64,
sender: Identity,
text: String,
}
// Define a reducer (your API endpoint)
#[spacetimedb::reducer]
pub fn send_message(ctx: &ReducerContext, text: String) {
ctx.db.messages().insert(Message {
id: 0,
sender: ctx.sender,
text,
});
}
```
On the client side, subscribe and get live updates:
```typescript
const [messages] = useTable(tables.message);
// messages updates automatically when the server state changes.
// No polling. No refetching.
```
## Use Cases
SpacetimeDB is well suited to web application backends, from everyday CRUD apps to reactive ones like collaborative tools, live dashboards, and chat. Write your module in TypeScript and connect from the browser with the [TypeScript SDK](https://spacetimedb.com/docs/clients/typescript), which includes React hooks like `useTable` and integrations for Vue, Svelte, Angular, and other frameworks. Each reducer runs as an ACID transaction, and subscribed clients receive committed changes automatically, so you don't need polling, a separate API server, or a pub/sub layer to keep them in sync. The `chat-react-ts` template from the Quick Start is a working example.
SpacetimeDB is optimized for low-latency transactional workloads like these, rather than batch processing or analytical queries.
## Durability
Every transaction that changes data is written to an on-disk [commitlog](https://spacetimedb.com/docs/reference/internals/commitlog), which is replayed to recover the database after a crash. Transactions are fsynced in batches, so many transactions share a single `fsync` (group commit) ([`local.rs`](crates/durability/src/imp/local.rs)).
Since SpacetimeDB 2.0, clients get [confirmed reads](https://spacetimedb.com/docs/upgrade#confirmed-reads-enabled-by-default) by default: the server holds back a transaction's subscription updates, and the caller's reducer result, until that transaction is durable ([`client_connection.rs`](crates/core/src/client/client_connection.rs)), so the data a client receives from its subscriptions and reducer calls will survive a crash. SQL queries over HTTP wait for durability by default too. On Maincloud and other replicated deployments, durable instead means [persisted by the replicas the database's replication settings require](https://spacetimedb.com/docs/clients/typescript#method-withconfirmedreads). Apps that can tolerate a client occasionally seeing a write that is then lost in a crash, like many games, can opt out with `withConfirmedReads(false)` for lower latency.
## Language Support
### Server Modules
Write your database logic in any of these languages:
| Language | Quickstart |
|----------|-----------|
| **Rust** | [Get started](https://spacetimedb.com/docs/quickstarts/rust) |
| **C#** | [Get started](https://spacetimedb.com/docs/quickstarts/c-sharp) |
| **TypeScript** | [Get started](https://spacetimedb.com/docs/quickstarts/typescript) |
| **C++** | [Get started](https://spacetimedb.com/docs/quickstarts/c-plus-plus) |
### Client SDKs
Connect from any of these platforms:
| SDK | Quickstart |
|-----|-----------|
| **TypeScript** (React, Next.js, Vue, Svelte, Angular, Node.js, Bun, Deno) | [Get started](https://spacetimedb.com/docs/quickstarts/react) |
| **Rust** | [Get started](https://spacetimedb.com/docs/quickstarts/rust) |
| **C#** (standalone and Unity) | [Get started](https://spacetimedb.com/docs/quickstarts/c-sharp) |
| **C++** (Unreal Engine) | [Get started](https://spacetimedb.com/docs/quickstarts/c-plus-plus) |
## Running with Docker
```bash
docker run --rm --pull always -p 3000:3000 clockworklabs/spacetime start
```
## Building from Source
If you need features from `master` that have not been released yet:
```bash
# Prerequisites: Rust toolchain with wasm32-unknown-unknown target
curl https://sh.rustup.rs -sSf | sh
git clone https://github.com/clockworklabs/SpacetimeDB
cd SpacetimeDB
cargo build --locked --release -p spacetimedb-standalone -p spacetimedb-update -p spacetimedb-cli
```
Then install the binaries:
<details>
<summary>macOS / Linux</summary>
```bash
mkdir -p ~/.local/bin
STDB_VERSION="$(./target/release/spacetimedb-cli --version | sed -n 's/.*spacetimedb tool version \([0-9.]*\);.*/\1/p')"
mkdir -p ~/.local/share/spacetime/bin/$STDB_VERSION
cp target/release/spacetimedb-update ~/.local/bin/spacetime
cp target/release/spacetimedb-cli ~/.local/share/spacetime/bin/$STDB_VERSION
cp target/release/spacetimedb-standalone ~/.local/share/spacetime/bin/$STDB_VERSION
# Add to your shell config if not already present:
export PATH="$HOME/.local/bin:$PATH"
# Set the active version:
spacetime version use $STDB_VERSION
```
</details>
<details>
<summary>Windows (PowerShell)</summary>
```powershell
$stdbDir = "$HOME\AppData\Local\SpacetimeDB"
$stdbVersion = & ".\target\release\spacetimedb-cli" --version |
Select-String -Pattern 'spacetimedb tool version ([0-9.]+);' |
ForEach-Object { $_.Matches.Groups[1].Value }
New-Item -ItemType Directory -Path "$stdbDir\bin\$stdbVersion" -Force | Out-Null
Copy-Item "target\release\spacetimedb-update.exe" "$stdbDir\spacetime.exe"
Copy-Item "target\release\spacetimedb-cli.exe" "$stdbDir\bin\$stdbVersion\"
Copy-Item "target\release\spacetimedb-standalone.exe" "$stdbDir\bin\$stdbVersion\"
# Add to your system PATH: %USERPROFILE%\AppData\Local\SpacetimeDB
# Then in a new shell:
spacetime version use $stdbVersion
```
</details>
Verify with `spacetime --version`.
To find your way around the code, see the [architecture diagram](docs/DEVELOP.md#architecture) of what runs inside SpacetimeDB Standalone.
## Documentation
To prepare your AI coding environment, follow the [agent setup guide](docs/static/agent-setup.md).
Full documentation is available at **[spacetimedb.com/docs](https://spacetimedb.com/docs)**, including:
- [Quickstart guides](https://spacetimedb.com/docs) for every supported language and framework
- [Core concepts](https://spacetimedb.com/docs/core-concepts): tables, reducers, subscriptions, authentication
- [Tutorials](https://spacetimedb.com/docs/tutorials/chat-app): chat app, Unity multiplayer, Unreal Engine multiplayer
- [Deployment guide](https://spacetimedb.com/docs/how-to/deploy/maincloud): publishing to Maincloud
- [CLI reference](https://spacetimedb.com/docs/cli-reference)
- [SQL reference](https://spacetimedb.com/docs/reference/sql/)
## License
SpacetimeDB is licensed under the [Business Source License 1.1 (BSL)](LICENSE.txt). It converts to the AGPL v3.0 with a linking exception after a few years. The linking exception means you are **not** required to open-source your own code if you use SpacetimeDB. You only need to contribute back changes to SpacetimeDB itself.
**Why did we choose this license?**
We chose to license SpacetimeDB under the MariaDB Business Source License for 4 years because we can't compete with AWS while also building our products for them.
We chose GPLv3 with linking exception as the open source license because we want contributions merged back into mainline (just like Linux), but we don't want to make anyone else open source their own code (i.e. linking exception).