---
id: flask-session
version: "0.8.0"
license: unclear
license_treatment: permissive
maintenance: aging
---

# Flask-Session — Server-side session support for Flask

License: permissive · Maintenance: aging · Downloads: 15.2M/mo

## 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 above — verify before relying.

Flask-Session adds server-side session storage to Flask applications, supporting multiple backends including Redis, Memcached, FileSystem, MongoDB, and SQLAlchemy.

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

pip install flask-session
uv add flask-session
poetry add flask-session

## Installing Flask-Session

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.

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)

Requires Python 3.8 or later. A session backend (Redis, Memcached, FileSystem, MongoDB, or SQLAlchemy) must be configured and available.

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: not declared (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 15.2M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

flask server-side sessions, flask session storage backend, flask redis sessions, flask memcached sessions, session management flask, persistent session storage, flask session configuration, session-management, flask-extension, backend-agnostic

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