======================= Developer documentation ======================= .. index:: developer To customize Fleio functionality, developers can use the Fleio backend API and write their own modules. Fleio itself works with a JavaScript & Angular frontend and an API backend written in Python, Django and Django REST framework (DRF). .. toctree:: :maxdepth: 1 developer/add-change-docker-files developer/frontend developer/angular-frontend-customization developer/build-frontend.rst developer/backend developer/using-api developer/billing-gateways developer/customization-options developer/python-signals Other documentation pages you may need for development work or to customize Fleio: * :doc:`/configuring/settings-file` * :doc:`/configuring/frontend-settings` * :doc:`/configuring/django-admin` * :doc:`/developer/billing-gateways` If you want to create a new language translation or customize Fleio texts see our open source internationalization project: https://github.com/fleio/fleio-i18n.