> ## Documentation Index
> Fetch the complete documentation index at: https://docs.shuttle.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Project configuration

> How to configure your Rust project for running on Shuttle

## Shuttle.toml

The file `Shuttle.toml` can be used for project-local configuration.
For the current options available, check out [Deployment files](/docs/files).

## Workspaces

Shuttle supports [cargo workspaces](https://doc.rust-lang.org/book/ch14-03-cargo-workspaces.html), but only one Shuttle service per workspace.
The first binary target using the `#[shuttle_runtime::main]` macro will be targeted for local runs and deployments.

If `Shuttle.toml` or [Secrets](/resources/shuttle-secrets) are used, those files should be placed in the root of the workspace.

This is an example of a workspace structure with shared code between a backend and frontend crate:

```text theme={null}
.
├── .gitignore
├── Cargo.toml
├── Secrets.toml      (optional)
├── Shuttle.toml      (optional)
├── backend/
│   ├── Cargo.toml    (depends on shuttle-runtime)
│   └── src/
│       └── main.rs   (contains #[shuttle_runtime::main])
├── frontend/
│   ├── Cargo.toml
│   └── src/
│       └── main.rs
└── shared/
    ├── Cargo.toml
    └── src/
        └── lib.rs
```

## Cargo feature flags

If the cargo feature `shuttle` exists, Shuttle activates it and disables default features.

In this example, Shuttle will enable the features `shuttle` and `bar`.
To use default features on Shuttle, add `default` to the shuttle array.

```toml Cargo.toml theme={null}
[features]
default = ["foo"]
shuttle = ["bar"]
foo = []
bar = []
```

## Multiple binaries

If you want to keep your project structured for allowing both running with and without Shuttle, check out the [standalone-binary](https://github.com/shuttle-hq/shuttle-examples/tree/main/other/standalone-binary) example. This is great for gradually adding Shuttle into your project.

## .shuttle/config.toml

The `.shuttle/config.toml` is created when linking your project folder to a Shuttle project.
It is added to `.gitignore` by default, and should not be committed.