---
id: fqdn
version: "1.5.1"
license: MPL 2.0
license_treatment: copyleft
maintenance: aging
---

# fqdn — Validates fully-qualified domain names against RFC 1123, so that they are acceptable to modern bowsers

License: copyleft · Maintenance: aging · Popularity: top 1,000 on PyPI

## Install

pip install fqdn
uv add fqdn
poetry add fqdn

## Description

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.. AMAZING REFERENCES
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.. |Python Versions| image:: https://img.shields.io/pypi/pyversions/fqdn.svg
   :target: https://pypi.org/project/fqdn/

.. |Build Status| image:: https://github.com/ypcrts/fqdn/actions/workflows/unit-tests.yml/badge.svg
   :target: https://github.com/ypcrts/fqdn/actions/workflows/unit-tests.yml

.. |Coverage Status| image:: https://codecov.io/gh/ypcrts/fqdn/branch/develop/graph/badge.svg?token=cavArywW2X
  :target: https://codecov.io/gh/ypcrts/fqdn

.. |Latest PyPI Version| image:: https://img.shields.io/pypi/v/fqdn.svg
   :target: https://pypi.python.org/pypi/fqdn

.. |Downloads| image:: https://pepy.tech/badge/fqdn
   :target: https://pepy.tech/project/fqdn

.. |Monthly Downloads| image:: https://pepy.tech/badge/fqdn/month
   :target: https://pepy.tech/project/fqdn/month

.. |License Status| image:: https://app.fossa.com/api/projects/git%2Bgithub.com%2Fypcrts%2Ffqdn.svg?type=shield
   :target: https://app.fossa.com/projects/git%2Bgithub.com%2Fypcrts%2Ffqdn?ref=badge_shield

.. |License Status...

## AI interpretation — verify before relying

Validates fully-qualified domain names (FQDNs) against RFC 1123 and related IETF specifications, with configurable strictness to allow relaxed hostname formats like those without periods or with underscores.

Verdict: A stable, low-friction FQDN validator with no known vulnerabilities and broad Python support (2.7, 3.5+). Aging maintenance (last release 2021) is offset by recent repo activity and production-grade status. MPL 2.0 copyleft applies only if you modify the package itself. Suitable for RFC-conformant hostname validation in DNS, email, and web contexts.

[View on SkillFed](https://skillfed.io/packages/fqdn) · [View on PyPI](https://pypi.org/project/fqdn/)