Deploy and Host Flask on Railway

Flask is a lightweight WSGI web framework for Python — small enough to read in an afternoon, flexible enough to grow into a real application. This template gives you a working Flask app served by gunicorn, with the runtime pinned so the deployment that works today still works next month.

About Hosting Flask

Deploying Flask means more than pushing app.py. You need a production WSGI server instead of the development one, a bind address the platform can actually reach, a pinned Python version so a builder upgrade cannot change your runtime underneath you, and a health check so a broken release is caught before it takes traffic. This template ships all four, wired up and verified on Railway.

Common Use Cases

A starting point for a Python API or web app you intend to grow
A small internal service — a webhook receiver, an admin endpoint, a scheduled job's HTTP face
A reference for how a Flask app should be configured for production hosting

Dependencies for Flask Hosting

Flask~=3.1.3 and gunicorn~=26.0.0 — patch updates arrive automatically, major versions do not

Deployment Dependencies

Implementation Details

Three choices make this deploy reliably:

The runtime is pinned. .python-version fixes Python at 3.13. The widely used Flask starter on Railway pins gunicorn==20.0.4, which imports pkg_resources — a module Python 3.12 no longer ships in a fresh virtualenv. When the builder's default Python moved to 3.12, that container began crash-looping with ModuleNotFoundError: No module named 'pkg_resources'. Gunicorn 26 does not import it, and a pinned Python means the runtime only changes when you change it.

The bind is explicit. gunicorn.conf.py reads PORT in Python:

bind = f"0.0.0.0:{os.environ.get('PORT', '8080')}"

so the start command is just gunicorn main:app — no shell expansion to get wrong, and the app is never left listening on localhost where the proxy cannot reach it.

Failures are visible. /health returns JSON and is wired to Railway's health check, so a bad release fails the deploy instead of quietly serving errors.

The app itself is deliberately small: a landing page, /api/info, and /health. Add routes to main.py, packages to requirements.txt, and push.

Why Deploy Flask on Railway?

Railway is a singular platform to deploy your infrastructure stack. Railway will host your infrastructure so you don't have to deal with configuration, while allowing you to vertically and horizontally scale it.

By deploying Flask on Railway, you are one step closer to supporting a complete full-stack application with minimal burden. Host your servers, databases, AI agents, and more on Railway.