structlog is licensed both under the Apache License, Version 2 and the MIT license.
The reason for that is to be both protected against patent claims by own contributors and still allow the usage within GPLv2 software. For more legal details, see this issue on the bug tracker of PyCA’s cryptography.
The full license texts can be also found in the source code repository:
structlog is written and maintained by Hynek Schlawack. It’s inspired by previous work done by Jean-Paul Calderone and David Reid.
The development is kindly supported by Variomedia AG.
The following folks helped forming structlog into what it is now:
Some of them disapprove of the addition of thread local context data. :)