I am currently working on a port of merchant that is framework agnostic ie a pure python library which will have two wrappers (at this moment) flask-merchant and django-merchant (what you have been using all these days).
Currently, only stripe gateway and integration work for flask-merchant and django-merchant. The code is in an alpha stage and will be refined in the coming days. Please review the code and critique. Hopefully, when it gets a little more stable, it will get merged upstream into agiliq's merchant tree.
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Cheers
Theju