flask-cors
A Flask extension simplifying CORS support
Decision gist · record as of 2026-08-14
Yes. Flask-CORS is actively maintained, has no known vulnerabilities, installs with minimal friction, and solves a common Flask problem with a straightforward API. The MIT license is permissive. Install it if you need CORS support in a Flask application.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.9 or later; Flask must be installed and running.
- Low friction: pure Python wheel with only three runtime dependencies (flask, Werkzeug, typing_extensions).
- Actively maintained with a recent release 67 days ago and ongoing repository activity.
License · maintenance · safety
MIT (permissive) — MIT license is permissive; you can use, modify, and distribute this package freely in commercial and open-source projects without significant legal constraints.
last release 2026-06-08 (67 days) · last repo commit 2026-06-09 · 932 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 60,435,146 downloads/mo, #504 on PyPI
Alternatives
Verify before relying
pip install flask-cors
from flask import Flask
from flask_cors import CORS
app = Flask(__name__)
CORS(app)
@app.route('/')
def hello():
return 'Hello, cross-origin-world!'- Whether credential-based CORS requests (cookies across domains) require additional CSRF protection beyond what the package provides by default.
- Performance characteristics when handling high volumes of cross-origin requests or complex per-resource CORS configurations.
What it is and what it does
Flask-CORS is a Flask extension that automatically handles CORS (Cross-Origin Resource Sharing) headers, allowing your Flask application to safely serve requests from different domains. By default, it enables CORS for all routes and origins with a single initialization call, though you can also configure it at the resource level or on individual routes using a decorator.
The package operates on a philosophy of simplicity: when you enable CORS, you typically want it enabled broadly rather than managing individual headers and methods per route. It depends on Flask, Werkzeug, and typing_extensions, all of which are standard in Flask ecosystems. The package explicitly disables cross-domain cookie submission by default for security reasons, and the documentation recommends adding CSRF protection if you need to enable credential-based requests.
Use it for
- Enable CORS globally on a Flask API so frontend applications hosted on different domains can make AJAX requests to it.
- Configure CORS selectively for specific API routes or path patterns using the resources parameter.
- Decorate individual Flask routes with @cross_origin() to enable CORS on a per-endpoint basis without modifying the app initialization.
- Debug CORS issues by enabling logging on the flask_cors logger to understand which headers and origins are being processed.
- Secure cross-origin requests by relying on the default credential-disabling behavior while adding CSRF protection when needed.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
Flask-CORS is actively maintained, has no known vulnerabilities, installs with minimal friction, and solves a common Flask problem with a straightforward API. The MIT license is permissive. Install it if you need CORS support in a Flask application.
Install
flask-cors on PyPI
Before you install
Low friction: pure Python wheel with only three runtime dependencies (flask, Werkzeug, typing_extensions). Actively maintained with a recent release 67 days ago and ongoing repository activity.
Requires Python 3.9 or later; Flask must be installed and running.
License in practice
MIT license is permissive; you can use, modify, and distribute this package freely in commercial and open-source projects without significant legal constraints.
Quickstart
pip install flask-cors
from flask import Flask
from flask_cors import CORS
app = Flask(__name__)
CORS(app)
@app.route('/')
def hello():
return 'Hello, cross-origin-world!'Verify before relying
- Whether credential-based CORS requests (cookies across domains) require additional CSRF protection beyond what the package provides by default.
- Performance characteristics when handling high volumes of cross-origin requests or complex per-resource CORS configurations.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release <4.0,>=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 3 packagesflaskWerkzeugtyping_extensions |
| Maintenance | Actively maintained 67 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 60,435,146 / month, #504 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Intended Audience :: DevelopersProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.9Topic :: Software Development :: Libraries :: Python Modules |
Evidence: flask_cors-6.0.5-py3-none-any.whl
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See also cherrypy-cors · invenio-rest · Sanic-Cors · django-cors-headers · quart-cors · aiohttp-cors · fastapi-cors · aiohttp-middlewares · Flask-JSON · flask-talisman