How to format pyproject.toml with taplo

by Tim Hopper

uv does not include a built-in formatter for pyproject.toml. Taplo is a TOML formatter and validator that keeps pyproject.toml files consistently styled across a project.

Format with uvx

Run taplo as a one-off command without installing it:

uvx taplo fmt pyproject.toml

To check formatting without modifying files (useful in CI):

uvx taplo check pyproject.toml

Configure taplo

Taplo works with zero configuration, but you can customize its behavior. Add a [tool.taplo] section to your pyproject.toml:

[tool.taplo]
include = ["pyproject.toml"]

[[tool.taplo.rule]]
include = ["pyproject.toml"]
keys = ["dependencies", "*-dependencies"]

[tool.taplo.rule.formatting]
reorder_keys = true

This configuration reorders keys within dependency tables alphabetically. For the full list of formatting options, see the Taplo configuration reference.

You can also use a standalone .taplo.toml file in your project root if you prefer to keep tool configuration separate.

Add taplo as a pre-commit hook

To run taplo automatically before each commit, add it to your .pre-commit-config.yaml:

repos:
  - repo: https://github.com/tamasfe/taplo
    rev: release-taplo-cli-0.9.3
    hooks:
      - id: taplo

For setup instructions, see How to set up pre-commit hooks for a Python project.

Learn More

Last updated on April 13, 2026

How to fix the "externally-managed-environment" error How to gradually adopt type checking in an existing Python project

Please submit corrections and feedback...