# Pipfile: Python Dependency Declaration Format


A Pipfile is a TOML-formatted file that declares a project's Python dependencies for use with [Pipenv](https://pydevtools.com/handbook/reference/pipenv.md). It was originally proposed as a successor to [requirements.txt](https://pydevtools.com/handbook/reference/requirements.md), adding structured runtime and development dependency sections alongside a paired `Pipfile.lock` for reproducible installs.

The standalone `pipfile` specification project at [pypa/pipfile](https://github.com/pypa/pipfile) has not seen substantive activity since 2019. The format lives on inside Pipenv, which reads and writes both the `Pipfile` and `Pipfile.lock`. The broader Python packaging ecosystem moved toward dependency declarations in [pyproject.toml](https://pydevtools.com/handbook/reference/pyproject.toml.md) under [PEP 621](https://pydevtools.com/handbook/explanation/what-is-pep-621-compatibility.md), and the two formats are no longer in active competition.

## File Structure

A Pipfile uses TOML syntax with named sections for sources, runtime packages, development packages, Python requirements, and project scripts:

```toml {filename="Pipfile"}
[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
requests = ">=2.28"
flask = "*"

[dev-packages]
pytest = ">=7.0"
ruff = "*"

[requires]
python_version = "3.12"

[scripts]
test = "pytest tests/"
start = "flask run"
```

The `*` value declares a package with no version constraint. Runtime dependencies live under `[packages]`, with development-only tooling under `[dev-packages]`. The `[requires]` section pins the Python version, and `[scripts]` defines named commands that Pipenv can invoke with `pipenv run <name>`.

## Pipfile.lock

Running `pipenv lock` resolves the loose constraints in a Pipfile against the configured indexes and writes a fully pinned `Pipfile.lock` that records every transitive dependency at an exact version, with content hashes for verification. The lockfile is the artifact responsible for reproducible installs across machines, while the Pipfile holds the human-authored constraints. See [What is a lockfile?](https://pydevtools.com/handbook/explanation/what-is-a-lock-file.md) for background on the pattern.

## Limitations

- Tied to Pipenv. No other widely used installer reads or writes the format directly, in contrast to `requirements.txt` (read by [pip](https://pydevtools.com/handbook/reference/pip.md), [uv](https://pydevtools.com/handbook/reference/uv.md), and most installers) and `pyproject.toml` (read by every standards-compliant build frontend and most modern package managers).
- Outside the standard track. The format predates [PEP 621](https://pydevtools.com/handbook/explanation/what-is-pep-621-compatibility.md) and was never standardized through the PEP process, so it carries none of the cross-tool guarantees that `pyproject.toml` provides.
- No project metadata. A Pipfile declares dependencies but cannot describe a distributable package (name, version, entry points, build configuration). Projects that need to publish to PyPI keep a separate `pyproject.toml` or `setup.py` alongside it.
- Stalled specification. The `pypa/pipfile` repository has been quiet for years, and changes to the format effectively ship as Pipenv changes rather than through a published spec.

## Migrating Off Pipfile

Projects moving from Pipenv to a [pyproject.toml](https://pydevtools.com/handbook/reference/pyproject.toml.md)-based workflow can map `[packages]` to `[project] dependencies`, `[dev-packages]` to `[dependency-groups]`, and `[requires] python_version` to `requires-python`. The [How to migrate from Pipenv to uv](https://pydevtools.com/handbook/how-to/how-to-migrate-from-pipenv-to-uv.md) guide walks through the translation in full and covers the automated `migrate-to-uv` tool that reads a `Pipfile` and `Pipfile.lock` directly.

Pipfile should not be confused with [pipenv](https://pydevtools.com/handbook/reference/pipenv.md), the tool that reads and writes the format, or with [pip](https://pydevtools.com/handbook/reference/pip.md), the standard installer that has no involvement with the Pipfile format despite the similar name.

## Learn More

- [How to migrate from Pipenv to uv](https://pydevtools.com/handbook/how-to/how-to-migrate-from-pipenv-to-uv.md)
- [Pipenv reference](https://pydevtools.com/handbook/reference/pipenv.md)
- [requirements.txt reference](https://pydevtools.com/handbook/reference/requirements.md)
- [pyproject.toml reference](https://pydevtools.com/handbook/reference/pyproject.toml.md)
- [What is a lockfile?](https://pydevtools.com/handbook/explanation/what-is-a-lock-file.md)
- [Pipfile specification on GitHub](https://github.com/pypa/pipfile)
- [Pipenv documentation: Pipfile and Pipfile.lock](https://pipenv.pypa.io/en/latest/pipfile.html)