> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/get-convex/convex-backend/llms.txt
> Use this file to discover all available pages before exploring further.

# Building from source

> Learn how to build the Convex Backend project from source

## Installing dependencies

You will need to first install the following dependencies if you don't already have them on your machine.

### Required tools

#### Just

[Just](https://github.com/casey/just) is used to execute scripts set up in the `Justfile`.

<CodeGroup>
  ```bash Cargo theme={null}
  cargo install just
  ```

  ```bash Homebrew theme={null}
  brew install just
  ```
</CodeGroup>

#### Node.js

Make sure you have Node.js version `20.19.5` (specified in `.nvmrc`).

We recommend installing Node.js via [nvm](https://github.com/nvm-sh/nvm#installing-and-updating).

```bash theme={null}
nvm use
```

#### Rust toolchain

The Convex local backend is written in Rust. Install Cargo and the Rust toolchain via [rustup](https://rustup.rs/).

The Rust nightly version specified in `rust-toolchain` will install automatically when you use rustup.

### JavaScript dependencies

The project uses [Rush](https://rushjs.io/) to manage packages in a monorepo.

<Steps>
  <Step title="Install Rush">
    ```bash theme={null}
    npm clean-install --prefix scripts
    ```
  </Step>

  <Step title="Install Convex JavaScript dependencies">
    ```bash theme={null}
    just rush install
    ```
  </Step>
</Steps>

## Building the backend

Build and run the local backend from the source in this repo:

```bash theme={null}
just run-local-backend
```

The backend will start on port 3210.

<Note>
  If this fails with an error "persisted db metadata ...", you might need to erase the local database:

  ```bash theme={null}
  rm convex_local_backend.sqlite3
  ```
</Note>

## Provisioning a demo app

This example demonstrates running the backend with the included demo project.

<Steps>
  <Step title="Start the backend">
    Run the local backend:

    ```bash theme={null}
    just run-local-backend
    ```
  </Step>

  <Step title="Set up the demo project">
    Navigate to the demo project and install dependencies:

    ```bash theme={null}
    cd npm-packages/demos/tutorial
    npm i
    ```
  </Step>

  <Step title="Run Convex dev">
    The Convex CLI watches for changes in the application source code and pushes the code to the backend.

    ```bash theme={null}
    just convex dev
    ```

    The `convex` script in `Justfile` automatically adds appropriate `--url` and `--admin-key` flags to point the CLI to the local backend.
  </Step>

  <Step title="Run the frontend">
    Start the demo Vite server:

    ```bash theme={null}
    npm run dev:frontend
    ```

    <Note>
      Unlike the hosted Convex workflow, don't run the `dev:backend` command since `convex dev` is already running.
    </Note>
  </Step>
</Steps>

## Useful CLI commands

When interacting with your backend, these CLI commands may be helpful:

* `just convex data` - Lists tables in your Convex deployment
* `just convex env` - Allows you to list/set/update/delete environment variables
* `just convex logs` - Streams out log lines to the terminal (includes all successful executions if `--success` is passed in)
* `just convex import` - Allows you to import tables
* `just convex export` - Allows you to export tables

<Warning>
  If you're using both the local backend and the hosted cloud platform, make sure to run `npx convex dev` or `just convex dev` before you start testing your client. The `dev` command will take care of updating your `.env.local` file with the correct `CONVEX_URL`.
</Warning>