Klaus Demo ~jonashaag/bjoern / 1.3

Tree @1.3 (Download .tar.gz)

bjoern: Fast And Ultra-Lightweight Asynchronous HTTP/1.1 WSGI Server

A screamingly fast, ultra-lightweight asynchronous WSGI server for CPython, written in C using Marc Lehmann's high performance libev event loop and Ryan Dahl's http-parser.

Why It's Cool

bjoern is the fastest, smallest and most lightweight WSGI server out there, featuring

  • ~ 1000 lines of C code
  • Memory footprint ~ 600KB
  • Single-threaded and without coroutines or other crap
  • Can bind to TCP host:port addresses and Unix sockets (thanks @k3d3!)
  • Full persistent connection ("keep-alive") support in both HTTP/1.0 and 1.1, including support for HTTP/1.1 chunked responses



Arch Linux
pacman -S libev
apt-get install libev-dev
Fedora, CentOS
yum install libev-devel
Mac OS X (using homebrew)
brew install libev
Your Contribution Here
Fork me and send a pull request


For most users, the easiest way to install bjoern is using pip. Make sure libev is installed and then:

pip install bjoern

You can also build bjoern by directly using the provided setup.py file (this is probably most useful if you actually want to hack on bjoern):

python setup.py install

On some Linux systems (notably Fedora and CentOS), the libev headers may be installed outside of the default include path. In order to build bjoern you will need to export CFLAGS when running setup.py, for instance:

CFLAGS=-I/usr/include/libev python setup.py install


# Bind to TCP host/port pair:
bjoern.run(wsgi_application, host, port)

# Bind to Unix socket:
bjoern.run(wsgi_application, 'unix:/path/to/socket')

# Bind to abstract Unix socket: (Linux only)
bjoern.run(wsgi_application, 'unix:@socket_name')

Alternatively, the mainloop can be run separately:

bjoern.listen(wsgi_application, host, port)

System Message: INFO/1 (<string>, line 73); backlink

Duplicate implicit target name: "libev".