Open edX

Open edX is a free, open-source learning platform originally built by MIT and Harvard, now governed by Axim Collaborative and a global community. It powers massive course catalogs (70,000 courses, 140M+ learners globally) and you can self-host it, inspect the code, customize every detail, and extend it with plugins.

Choose Open edX if you want control, transparency, and zero vendor lock-in, or if you're part of a university, nonprofit, or large institution that can host and maintain the infrastructure. The learning curve is steeper than commercial LMS tools because you're responsible for hosting and troubleshooting, but the freedom and cost savings justify that for serious education organizations that want customization and scalability without licensing fees.