Senior Software Engineer; Privacy​/ago

Senior Software Engineer (Privacy)

Timezone preference: GMT-5 through GMT+1

The Wikimedia Foundation seeks a Senior Software Engineer to join the Product Safety and Integrity team. This hands-on engineering role focuses on building new security features to protect Wikipedia and other Wikimedia projects. You will collaborate with engineers and product managers to design and implement features that protect users and ensure the platform remains resilient against attacks.

We are looking for a seasoned software engineer experienced in building security features within large-scale systems. Candidates must understand the importance of testing, documentation, and mitigating common pitfalls in developing secure web applications. A passion for the WMF mission is essential. We operate transparently, impacting thousands of editors daily.

This role primarily involves working on the Media Wiki platform, which powers Wikipedia. As a top 10 global website, we require stringent performance standards while addressing complex security challenges. Key areas include supporting modern authentication technologies, detecting and preventing platform abuse (e.g., bots), and improving security architecture to defend against emerging threats.

• Help design, develop, and deliver security features, prioritizing safety and security.
• Collaborate with other engineering teams to ensure safe and compliant architectural and implementation choices.
• Lead by example in code review, decision-making, and team culture — fostering transparency, empathy, and collaboration.
• Develop, review, and deploy security features created by the Foundation and community members.
• Conduct internal and external security and privacy reviews.
• Perform maintenance and address technical debt in security and privacy-critical components.
• Provide support for application security and privacy incidents and operations.

We prioritize mindset and potential over a specific checklist of experiences.

• 5+ years of experience as a software engineer, ideally focused on security or privacy.
• Ability to work effectively in a modern web application environment (mostly PHP and JavaScript).
• Sufficient engineering and back-end web development experience to quickly learn PHP, if deep PHP experience is lacking.
• Drive technical quality and operational excellence by defining and reinforcing standards in testing, observability, and system reliability.
• Comfortable and autonomous in creating proofs of concept, writing design documents, and breaking down complex projects into actionable tasks to support less experienced team members.
• Experience developing secure software or security and privacy-related product features.
• Strong interest in working with a talented security team and learning specialist security skills, such as exploiting and mitigating application-level vulnerabilities.
• Ability to explain complex security issues and their implications on privacy and risk to non-technical audiences.
• Sensitivity to the security and privacy challenges faced by participants in a large, international project.
• Experience working in a remote, distributed team.

• Experience working on anti-abuse mechanisms, such as detecting bots or coordinated activity.
• Previous experience building security countermeasures against attacks on web, backend, and database technologies.
• Experience finding and fixing security bugs and reviewing code for security gaps.
• Working knowledge of threat modeling, secure design patterns, and privacy by design.
• Prior experience with Media Wiki or Wikimedia projects.
• Contributions to open-source software.

The Wikimedia Foundation is the nonprofit organization operating Wikipedia and the other Wikimedia free knowledge projects. Our vision is a world where every human can freely share in the sum of all knowledge. We host the projects, build software experiences for reading, contributing, and sharing content, support volunteer communities, and advocate for policies enabling free knowledge to thrive.

The Foundation is a charitable, not-for-profit organization relying on donations from millions of individuals globally (average donation ~$15), institutional grants, and gifts. We are a United States 501(c)(3) tax-exempt organization with offices in San Francisco, California, USA.

We are an equal opportunity employer committed to maintaining a diverse, inclusive, and equitable workplace. We encourage applicants from diverse backgrounds. We are a remote-first organization with staff and contractors based in 40+ countries.

Salaries are competitive, equitable, and consistent with our values. The anticipated annual pay range for US-based applicants is US $113,082 to US $175,725, determined by individualized factors including cost of living in the location. For applicants outside the US, the pay range will be adjusted to the country of hire. Compensation is based on skills,…