SpacetimeDB/templates/tanstack-ts

Get a SpacetimeDB app with TanStack Start running in under 5 minutes.

Prerequisites

• Node.js 18+ installed
• SpacetimeDB CLI installed

Install the SpacetimeDB CLI before continuing.

---

Create your project

Run the spacetime dev command to create a new project with a SpacetimeDB module and TanStack Start.

This will start the local SpacetimeDB server, publish your module, generate TypeScript bindings, and start the development server.

spacetime dev --template tanstack-ts

Open your app

Navigate to http://localhost:5173 to see your app running.

The template includes a TanStack Start app with TanStack Query integration with SpacetimeDB.

Explore the project structure

Your project contains both server and client code.

Edit spacetimedb/src/index.ts to add tables and reducers. Edit src/routes/index.tsx to build your UI.

my-spacetime-app/
├── spacetimedb/          # Your SpacetimeDB module
│   └── src/
│       └── index.ts      # Server-side logic
├── src/                  # TanStack Start frontend
│   ├── router.tsx        # QueryClient + SpacetimeDB setup
│   ├── routes/
│   │   ├── __root.tsx    # Root layout
│   │   └── index.tsx     # Main app component
│   └── module_bindings/  # Auto-generated types
└── package.json

Understand tables and reducers

Open spacetimedb/src/index.ts to see the module code. The template includes a person table and two reducers: add to insert a person, and sayHello to greet everyone.

Tables store your data. Reducers are functions that modify data — they're the only way to write to the database.

import { schema, table, t } from 'spacetimedb/server';

const spacetimedb = schema({
  person: table(
    { public: true },
    {
      name: t.string(),
    }
  ),
});
export default spacetimedb;

export const add = spacetimedb.reducer(
  { name: t.string() },
  (ctx, { name }) => {
    ctx.db.person.insert({ name });
  }
);

export const sayHello = spacetimedb.reducer(ctx => {
  for (const person of ctx.db.person.iter()) {
    console.info(`Hello, ${person.name}!`);
  }
  console.info('Hello, World!');
});

Test with the CLI

Open a new terminal and navigate to your project directory. Then use the SpacetimeDB CLI to call reducers and query your data directly.

cd my-spacetime-app

# Call the add reducer to insert a person
spacetime call add Alice

# Query the person table
spacetime sql "SELECT * FROM person"
 name
---------
 "Alice"

# Call sayHello to greet everyone
spacetime call say_hello

# View the module logs
spacetime logs
2025-01-13T12:00:00.000000Z  INFO: Hello, Alice!
2025-01-13T12:00:00.000000Z  INFO: Hello, World!

Query and update data

Use useSpacetimeDBQuery() to subscribe to tables with TanStack Query — it returns [data, loading, query]. SpacetimeDB React hooks also work with TanStack Start.

import { useSpacetimeDBQuery, useReducer } from 'spacetimedb/tanstack';
import { tables, reducers } from '../module_bindings';

function App() {
  const [people, loading] = useSpacetimeDBQuery(tables.person);
  const addPerson = useReducer(reducers.add);

  if (loading) return <p>Loading...</p>;

  return (
    <ul>
      {people.map((person, i) => (
        <li key={i}>{person.name}</li>
      ))}
    </ul>
  );
}

Next steps

• See the Chat App Tutorial for a complete example
• Read the TypeScript SDK Reference for detailed API docs