# Building distributions

To distribute your project to others (e.g., to upload it to an index like PyPI), you'll need to
build it into a distributable format.

Python projects are typically distributed as both source distributions (sdists) and binary
distributions (wheels). The former is typically a `.tar.gz` or `.zip` file containing the project's
source code along with some additional metadata, while the latter is a `.whl` file containing
pre-built artifacts that can be installed directly.

## Using `uv build`

`uv build` can be used to build both source distributions and binary distributions for your project.
By default, `uv build` will build the project in the current directory, and place the built
artifacts in a `dist/` subdirectory:

```console
$ uv build
$ ls dist/
example-0.1.0-py3-none-any.whl
example-0.1.0.tar.gz
```

You can build the project in a different directory by providing a path to `uv build`, e.g.,
`uv build path/to/project`.

`uv build` will first build a source distribution, and then build a binary distribution (wheel) from
that source distribution.

You can limit `uv build` to building a source distribution with `uv build --sdist`, a binary
distribution with `uv build --wheel`, or build both distributions from source with
`uv build --sdist --wheel`.

## Build constraints

`uv build` accepts `--build-constraint`, which can be used to constrain the versions of any build
requirements during the build process. When coupled with `--require-hashes`, uv will enforce that
the requirement used to build the project match specific, known hashes, for reproducibility.

For example, given the following `constraints.txt`:

```text
setuptools==68.2.2 --hash=sha256:b454a35605876da60632df1a60f736524eb73cc47bbc9f3f1ef1b644de74fd2a
```

Running the following would build the project with the specified version of `setuptools`, and verify
that the downloaded `setuptools` distribution matches the specified hash:

```console
$ uv build --build-constraint constraints.txt --require-hashes
```