> Markdown version of [/jobs/ext/2067400-software-engineer-iii](https://www.wearedevelopers.com/jobs/ext/2067400-software-engineer-iii). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Software Engineer III - **Company:** Wikimedia Foundation - **Location:** Spain - **Contract:** Permanent contract - **Skills:** JavaScript (Programming Language), PHP (Programming Language), Application Programming Interfaces (APIs), Unit Testing, Cascading Style Sheets (CSS), Code Review, Text Processing, Python (Programming Language), Open Source Technology, Open Access, Performance Tuning, Ruby, Software Engineering, Scripting, Information Technology, Free and Open-Source Software, Wikis, Wikimedia, Software Version Control - **Published:** August 15, 2026 - **Apply:** https://es.trabajo.org/oferta-5355-26827c0a7c0c12540fb21c1293be4876 ## About the Role development using a scripting language (such as JavaScript, PHP, Python or Ruby). Most of our work is in JavaScript, PHP and CSS. - Focused software engineering: you have experience of writing unit tests, and of structuring your work with version control. - Strong written communication skills as our collaboration largely happens online, on chats, wikis, documents and tickets. Qualities that are important to us: - A desire to make meaningful contributions to knowledge equity, free culture, and open access. - An emphasis on communicating clearly in both synchronous and asynchronous channels. - A strong aptitude in algorithms and data structures is essential - A desire to write well-documented and maintainable code. - The willingness to participate in technical discussions, proposing solutions to technical challenges, participating in code reviews and receiving feedback. - An eagerness and curiosity to solve technical problems, trying things out and investigating issues, and supporting the work of others. Additionally, we'd love it if you have this: - Experience building a rich-text editor. - Experience working with large, legacy codebases. - A history of editing on Wikimedia projects. - A history of open-source contribution. - Bachelor's degree in computer science or mathematics, or equivalent experience. We'd love to hear from you - even if you don't meet 100% of the criteria listed here. Most important is the aptitude to solve hard problems. Algorithms and data structures are extremely important in our products, so if this sounds interesting, come and talk to us About the Wikimedia Foundation The Wikimedia Foundation is the nonprofit organization that operates Wikipedia and the other Wikimedia free knowledge projects. Our vision is a world in which every single human can freely share in the sum of all knowledge. We believe that everyone has the potential to contribute something to our ## Description (e.g. DiscussionTools to support on-wiki communication) and unlock new capabilities that lower the barriers people encounter when contributing to Wikipedia. The latest capability being Edit Check , an open-ended system designed to surface actionable pieces of feedback and suggestions that help volunteers improve the quality and integrity of the information Wikipedia offers. You are responsible for: - Improving the Wikipedia product experience by fixing bugs and implementing new functionality. - Iterating on new features through collaboration with fellow engineers, product managers, designers, other teams, and community members. - Writing multilingual, accessible, and performant code using Javascript and PHP. - Building on top of the MediaWiki API ecosystem. - Instrumenting components to monitor feature behavior and quality characteristics. 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