OpenAtlas builds on open source technology, is and will always be free and open source to guarantee continued usage.
The code is freely available on GitHub. Below used technologies are listed.

Python is an interpreted, high-level, general-purpose programming language.
Website: https://www.python.org
Licence: Python Software Foundation License

Flask is a micro web framework written in Python with the ability to scale up to complex applications.
Website: https://palletsprojects.com/p/flask/
Licence: BSD

PostgreSQL is a free and open-source relational database management system.
Website: https://www.postgresql.org/
Licence: PostgreSQL License

PostGIS is a spatial database extender for PostgreSQL and adds support for geographic objects .
Website: https://postgis.net
Licence: GPL 2 or later

Bootstrap is a free and open-source CSS framework.
Website: https://getbootstrap.com/
Licence: MIT

Leaflet is a open source JavaScript library used to build web mapping applications.
Website: https://leafletjs.com/
Licence: BSD-2-Clause

Jinja is a full-featured template engine for Python with full unicode support.
Website: https://palletsprojects.com/p/jinja/
Licence: BSD

Apache is a free and open-source cross-platform web server software.
Website: https://httpd.apache.org/
Licence: Apache License 2.0