flask-babel
Adds i18n/l10n support for Flask applications.
What it is and what it does
Flask-Babel integrates the Babel and pytz libraries into Flask applications to provide internationalization and localization capabilities. It handles message translation, date and time formatting across different locales, and timezone conversions, allowing a single Flask application to serve content in multiple languages and regional formats.
The package works by decorating your Flask app with Babel support, then using Babel's translation and formatting functions within your templates and Python code. It relies on Flask, Babel, pytz, and Jinja2 as runtime dependencies. The project is in production-stable status and supports Python 3.8 through 3.11, though maintenance has been dormant since late 2023.
Use it for:
- Build a Flask web application that serves the same content in multiple languages based on user preference or browser locale.
- Format dates, times, and numbers according to regional conventions (e.g., DD/MM/YYYY vs MM/DD/YYYY) without manual logic.
- Display timezone-aware timestamps correctly for users in different geographic regions.
- Translate user-facing strings in Jinja2 templates and Python view functions using gettext-style message catalogs.
- Support currency and number formatting that respects locale-specific conventions (decimal separators, thousand separators).
Worth the install?
AI-flagged interpretation of the facts on this page — verify before relying
Adds internationalization (i18n) and localization (l10n) support to Flask applications using Babel and pytz for date, time, and message translation.
Yes, if you need i18n/l10n in a Flask application. The package is production-stable, has low install friction, and no known vulnerabilities. The dormant maintenance is a minor concern—verify compatibility with your Flask and Babel versions before adopting, but the established user base and simple dependency chain make it a reliable choice for multi-language Flask projects.
Install
flask-babel on PyPI
pip
pip install flask-babeluv
uv add flask-babelpoetry
poetry add flask-babelInstalling flask-babel
Before you install
Low install friction with a pure-Python wheel distribution. Dormant maintenance status (last commit 2024-08-07, no release since 2023-10-02) but stable and widely used in production; 452 repository stars indicate established adoption.
License in practice
BSD-3-Clause is permissive; you can use, modify, and distribute this package freely in commercial and private projects with minimal restrictions.
Quickstart
pip install flask-babel
from flask import Flask
from flask_babel import Babel
app = Flask(__name__)
Babel(app)
Verify before relying
- Whether dormant maintenance (last release over 10 months old) affects compatibility with recent Flask or Babel versions.
- Whether the package handles all modern locale and timezone edge cases or if newer alternatives are more actively maintained.
Package facts
| License | BSD-3-Clause (permissive) |
| Python support | supports the current Python release (>=3.8,<4.0) |
| Install friction | low — pure-Python wheel |
| Runtime dependencies | 4 — pytz, Flask, Babel, Jinja2 |
| Maintenance | dormant — 1,047 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 15,609,483/month — #1,179 on PyPI (30-day window, as of 2026-08-14) |
| Known vulnerabilities | none known (OSV.dev, checked 2026-08-14) |
Evidence: flask_babel-4.0.0-py3-none-any.whl
Tags
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