Flask-SocketIO
Socket.IO integration for Flask applications
Decision gist · record as of 2026-08-14
Yes. Flask-SocketIO is actively maintained, has low install friction, carries a permissive MIT license, and solves a real problem—adding WebSocket support to Flask with minimal boilerplate. It's in the top 5000 packages by downloads and has no known vulnerabilities. Install it if you need real-time bidirectional communication in a Flask app.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.8 or later; production deployment typically needs a production WSGI server and may require additional configuration for WebSocket support.
- Low friction install with a pure-Python wheel.
- Actively maintained with recent releases; last commit 2026-07-30 and 5508 repository stars indicate ongoing support.
License · maintenance · safety
permissive license (permissive) — MIT license (permissive) means you can use, modify, and distribute this package freely in commercial and private projects with minimal restrictions.
last release 2026-02-21 (174 days) · last repo commit 2026-07-30 · 5,508 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 5,242,836 downloads/mo, #2,130 on PyPI
Alternatives
Verify before relying
pip install flask-socketio
from flask import Flask
from flask_socketio import SocketIO, emit
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app)
@socketio.event
def my_event(message):
emit('my_response', {'data': 'got it!'})
if __name__ == '__main__':
socketio.run(app)- Whether the package handles reconnection and fallback transports automatically or requires manual configuration.
- Performance characteristics and scalability limits for concurrent connections.
- Specific deployment requirements beyond standard Flask WSGI servers.
What it is and what it does
Flask-SocketIO bridges Flask applications with Socket.IO, a library that enables real-time, event-driven communication between server and client over WebSockets. It wraps the python-socketio package and integrates it into Flask's request/response model, letting you define event handlers as decorators and emit messages bidirectionally. The package depends on flask, python-socketio, werkzeug, jinja2, click, and blinker—all standard Flask ecosystem components.
Typical use is defining server-side event handlers with @socketio.event decorators, then running the app with socketio.run() instead of app.run(). Clients connect via a JavaScript Socket.IO client library and exchange JSON-serializable messages. This pattern is common for live dashboards, collaborative tools, notifications, and any application where the server needs to push updates to connected clients without polling.
Use it for
- Build live notification systems where the server pushes alerts to connected browsers in real time.
- Create collaborative editing or whiteboarding applications with instant synchronization across clients.
- Implement live dashboards and monitoring interfaces that update without page refresh.
- Add real-time chat or messaging features to Flask web applications.
- Stream live data (stock prices, sensor readings, game state) to multiple clients simultaneously.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
Flask-SocketIO is actively maintained, has low install friction, carries a permissive MIT license, and solves a real problem—adding WebSocket support to Flask with minimal boilerplate. It's in the top 5000 packages by downloads and has no known vulnerabilities. Install it if you need real-time bidirectional communication in a Flask app.
Install
flask-socketio on PyPI
Before you install
Low friction install with a pure-Python wheel. Actively maintained with recent releases; last commit 2026-07-30 and 5508 repository stars indicate ongoing support.
Requires Python 3.8 or later; production deployment typically needs a production WSGI server and may require additional configuration for WebSocket support.
License in practice
MIT license (permissive) means you can use, modify, and distribute this package freely in commercial and private projects with minimal restrictions.
Quickstart
pip install flask-socketio
from flask import Flask
from flask_socketio import SocketIO, emit
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app)
@socketio.event
def my_event(message):
emit('my_response', {'data': 'got it!'})
if __name__ == '__main__':
socketio.run(app)Verify before relying
- Whether the package handles reconnection and fallback transports automatically or requires manual configuration.
- Performance characteristics and scalability limits for concurrent connections.
- Specific deployment requirements beyond standard Flask WSGI servers.
Package facts
| License | permissive license permissive |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 7 packagesblinkerclickflaskFlaskjinja2python-socketiowerkzeug |
| Maintenance | Actively maintained 174 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 5,242,836 / month, #2,130 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Environment :: Web EnvironmentIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: Python :: 3 |
Evidence: flask_socketio-5.6.1-py3-none-any.whl
Tags
Let your AI agent find packages like this
Example. Real query, live index.
You found this page by searching. An agent finds it by wishing: SkillFed indexes 14,416 PyPI packages by what they can do, searchable in plain language.
wish › “real-time communication python”
- Flask-SocketIOFlask-SocketIO adds real-time bidirectional communication to Flask…
- ws4pyws4py implements the WebSocket protocol (RFC 6455) for Python,…
- lcmLCM provides publish/subscribe message passing and automatic data…
Give your agent the search over MCP, or paste the wish link into any chat.
More Dynamic Content packages
MarkupSafe provides a text object that escapes special characters so untrusted strings can be safely embedded in HTML and XML without injection attacks.
Jinja2 is a templating engine that renders dynamic content by combining templates with Python-like syntax and data, supporting template inheritance, macros, autoescaping, and sandboxed execution.
Soupsieve is a CSS selector library designed to work with Beautiful Soup 4 to select, match, and filter HTML and XML elements using modern CSS selectors from CSS level 1 through CSS level 4 specifications.
Install it if you use Beautiful Soup for HTML or XML parsing and want modern CSS selector support.
Werkzeug is a WSGI utility library providing request/response objects, URL routing, an interactive debugger, HTTP utilities, and a development server for building web applications.
Flask is a lightweight WSGI web application framework for building web applications in Python, from simple single-page sites to complex multi-route applications.
Mako compiles Python-embedded templates into Python modules for fast rendering, supporting layout inheritance, custom functions, and direct Python expressions within template syntax.
See also fastapi-socketio · flask-sock · python-socketio · simple-websocket · python-engineio · websocket · bottle-websocket · ws4py · gevent-websocket · websockets