What Gunicorn is
Gunicorn is a WSGI server that runs Python web applications behind a reverse proxy. It names itself in the server header, so it is one of the few reliable public indicators that a response came from Python.
How DNSTrace.dev detects it
Detection reads the final HTTPS response and the first bytes of its markup. One matching signal is reported as strong evidence; two or more independent signals are reported as confirmed.
server header naming gunicorn— Emitted by Gunicorn unless a proxy in front replaces the header.
What a detection proves
A Python WSGI application served the response through Gunicorn.
What it does not prove
Which framework runs on it. Django and Flask are both common, and neither is identified by this signal alone.
Common questions
Why is the framework not named?
Gunicorn runs the application; the framework does not usually add a header of its own.
Does a proxy hide it?
Often. Nginx or a CDN in front commonly replaces the server header.
Compare with
DjangoOpen source, Django Software Foundation
Server language
PHPOpen source, the PHP Group
Application runtime
Java servlet containerVarious, Jakarta EE standard
Elixir application framework
PhoenixOpen source
Check a domain
Run a full lookup to see the delivery layer, the detected application stack, live TLS and the announcing network side by side.