Flask-Session
Server-side session support for Flask
Decision gist · record as of 2026-08-14
Yes, with conditions. Flask-Session is a stable, permissive-licensed extension from the Pallets Team with low install friction and no known vulnerabilities. It is worth installing if you need server-side session storage for a Flask application. However, the aging maintenance status means you should verify compatibility with your target Flask and Python versions before committing to production use.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.8 or later.
- A session backend (Redis, Memcached, FileSystem, MongoDB, or SQLAlchemy) must be configured and available.
- Low install friction with three straightforward runtime dependencies.
License · maintenance · safety
permissive license (permissive) — Permissive license allows commercial and private use without restriction.
last release 2024-03-26 (871 days) · last repo commit 2025-06-14 · 534 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 15,174,209 downloads/mo, #1,195 on PyPI
Alternatives
Verify before relying
pip install flask-session
from flask import Flask, session
from flask_session import Session
app = Flask(__name__)
app.config['SESSION_TYPE'] = 'redis'
Session(app)- Whether the aging maintenance status affects stability or security for current Flask versions.
- Performance characteristics and scalability limits across different storage backends.
- Compatibility with Python versions beyond 3.8.
What it is and what it does
Flask-Session is a Flask extension that replaces Flask's default client-side cookie sessions with server-side session storage. Instead of storing all session data in encrypted cookies sent to the client, Flask-Session keeps session data on the server and uses a session ID cookie for client identification. This approach is more secure for sensitive data and supports larger session payloads.
The extension abstracts away the complexity of choosing and configuring a session backend. It supports Redis, Memcached, FileSystem, MongoDB, and SQLAlchemy as storage options, allowing you to pick the backend that fits your infrastructure. You configure the session type via Flask's config system, initialize the extension with your app, and then use Flask's standard session object—the storage mechanism is transparent to your route handlers.
Use it for
- Store authentication tokens and user state server-side for web applications requiring secure session handling.
- Implement distributed session storage across multiple application servers using Redis or Memcached.
- Persist session data to a relational database using SQLAlchemy for applications with existing database infrastructure.
- Scale Flask applications horizontally while maintaining consistent session state across instances.
- Migrate from client-side cookies to server-side storage without rewriting session access code.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, with conditions.
Flask-Session is a stable, permissive-licensed extension from the Pallets Team with low install friction and no known vulnerabilities. It is worth installing if you need server-side session storage for a Flask application. However, the aging maintenance status means you should verify compatibility with your target Flask and Python versions before committing to production use.
Install
flask-session on PyPI
Before you install
Low install friction with three straightforward runtime dependencies. Maintenance status is aging—last release was 2024-03-26 with no updates since—but the repository remains active and backed by the Pallets Team.
Requires Python 3.8 or later. A session backend (Redis, Memcached, FileSystem, MongoDB, or SQLAlchemy) must be configured and available.
License in practice
Permissive license allows commercial and private use without restriction.
Quickstart
pip install flask-session
from flask import Flask, session
from flask_session import Session
app = Flask(__name__)
app.config['SESSION_TYPE'] = 'redis'
Session(app)Verify before relying
- Whether the aging maintenance status affects stability or security for current Flask versions.
- Performance characteristics and scalability limits across different storage backends.
- Compatibility with Python versions beyond 3.8.
Package facts
| License | permissive license permissive |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 3 packagesflaskmsgspeccachelib |
| Maintenance | Aging 871 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 15,174,209 / month, #1,195 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaEnvironment :: Web EnvironmentFramework :: FlaskIntended Audience :: DevelopersLicense :: OSI Approved :: BSD LicenseOperating System :: OS IndependentProgramming Language :: PythonTopic :: Internet :: WWW/HTTP :: SessionTopic :: Internet :: WWW/HTTP :: WSGITopic :: Internet :: WWW/HTTP :: WSGI :: ApplicationTopic :: Software Development :: Libraries :: Application Frameworks |
Evidence: flask_session-0.8.0-py3-none-any.whl
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See also Beaker · Frozen-Flask · flask-redis · pyramid-session-redis · Flask-SQLAlchemy · Flask · Flask-Login · Flask-Caching · Flask-Security · Flask-Security-Too