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Free for Open Source

Rocket Validator stands on the shoulders of giants - it wouln't be possible without the existence of open source software.

That's why we want to give something back to the community - by checking their sites for free, helping open source contributors to fix HTML and accessibility issues.

Site reports are updated once a week. If you'd like to add an open source project to this list, just contact us.

Launch, manage, and scale ambitious digital experiences—with the flexibility to build great websites or push beyond the browser.

Elixir is a dynamic, functional language designed for building scalable and maintainable applications. Elixir leverages the Erlang VM, known for running low-latency, distributed and fault-tolerant systems.


The package manager for the Erlang ecosystem. Hex holds a huge open source repository of Erlang and Elixir libraries.

Ruby is a dynamic, open source programming language with a focus on simplicity and productivity. It has an elegant syntax that is natural to read and easy to write. is the Ruby community’s gem hosting service. Instantly publish your gems and then install them. Use the API find out more about available gems.

The framework of choice by thousands of developers looking for a happy, productive way of building modern web applications. The community-maintained guides are just excellent!

Open Government and E-Participation Portal for the city of Madrid.

Open Government and E-Participation Portal for the city of Barcelona.