Senior Software Engineer, Privacy

Mozilla; España; Remote; EUR 70,000 - 100,000; Full time

Benefits offered by this job

Bonus plans

Retirement contributions

Wellness days

Holidays + birthday

Home office stipend

Professional development budget

Parental leave

Employee referral program

Life/AD&D/Disability insurance

Job summary

Mozilla is seeking a Senior Software Engineer to join the Privacy Team and advance the Firefox Web Platform. You will work on privacy protections, anti-tracking, and threat intelligence, contributing to Gecko and the broader browser stack.

This role supports a remote arrangement within Spain, collaborating across Europe and the US. Ideal candidates have 4+ years in C++/Rust, strong memory-safety and multi-threading knowledge, and a track record of delivering complex features on tight schedules.

Qualifications

• BS in CS or related field, or equivalent experience.
• 4+ years in C++ and Rust.
• Experience with multi-threading and memory safety.
• Proven ability to deliver complex features on schedule.
• Strong written and verbal communication.

Responsibilities

• Implement privacy protections into Firefox to reduce tracking.
• Improve Gecko architecture and performance.
• Develop C++, JavaScript, and Rust components end-to-end.
• Collaborate with distributed teams across Europe and US.

Skills

C++

Rust

Memory safety

Multi-threaded

Open source

Communication

Education

Bachelor's degree in CS

Tools

Gecko

Python

SQL

Job description

The Mozilla Corporation is wholly owned by the non-profit 501(c) Mozilla Foundation. This means we aren’t beholden to any shareholders — only to our mission. Along with thousands of volunteer contributors and collaborators all over the world, Mozillians design, build and distribute open-source software that enables people to enjoy the internet on their terms.

About this team and role:

Mozilla exists to build the Internet as a public resource accessible to all because we believe that open and free is better than closed and restricted. We are looking for a Senior Software Engineer to support the Privacy Team to advance the Firefox Web Platform.

Are you passionate about Privacy Protections and the Open Web? Do you want to ship software to a large user base? Do you want your contributions to have a positive impact on the world? Do you want to advance current browser architecture to make the web a safer place for users?

Why Mozilla?

Mozilla Corporation is the non-profit-backed technology company that has shaped the internet for the better over the last 25 years. We make pioneering brands like Firefox, the privacy-minded web browser. Now, with more than 225 million people around the world using our products each month, we’re shaping the next 25 years of technology and helping to reclaim an internet built for people, not companies. Our work focuses on diverse areas including AI, social media, security and more. And we’re doing this while never losing our focus on our core mission – to make the internet better for people.

What you'll do:

• Implement Privacy-improving, anti-tracking and threat intelligence protection into the Firefox web browser to mitigate user tracking and phishing.
• Implement architectural improvements into Gecko, the browser engine underlying Firefox.
• Build performant, low-latency, and maintainable C++, JavaScript and Rust code
• Work as part of a geographically distributed team in an asynchronous manner (mostly Europe and US-East).

What you'll bring:

• Bachelor's degree in computer science, engineering, or a related program; or equivalent work experience.
• At least 4 years of experience with programming in C++ and Rust, with a strong background in memory safety, multi-threaded system architecture, or raw data stream manipulation.
• Proven ability to onboard quickly, deliver and improve complex software projects.
• Proven track record of independently scoping and landing complex features within tight release windows.
• Excellent written and verbal communication skills. You can validate your progress and decisions and communicate them clearly.

Bonus Points:

• You have already contributed to the Mozilla mission and the codebase.
• Experience working within the browser space (Gecko, Chromium, WebKit) or web engine runtime abstractions.
• Experience or high interest in designing or leveraging ML pipelines to automate internal developer workflows.
• Deep understanding of web architecture, the privacy/security model of the web, and client-side data structures.
• Knowledge of basic statistical modeling.
• Proficiency with Python and SQL.

What you’ll get:

• Generous performance-based bonus plans to all eligible employees - we share in our success as one team
• Generous retirement contributions with 100% immediate vesting (regardless of whether you contribute)
• Quarterly all-company wellness days where everyone takes a pause together
• Country specific holidays plus a day off for your birthday
• One-time home office stipend
• Annual professional development budget
• Quarterly well-being stipend
• Considerable paid parental leave
• Employee referral bonus program
• Other benefits (life/AD&D, disability, EAP, etc. - varies by country)

About Mozilla

Mozilla exists to build the Internet as a public resource accessible to all because we believe that open and free is better than closed and controlled. When you work at Mozilla, you give yourself a chance to make a difference in the lives of Web users everywhere. And you give us a chance to make a difference in your life every single day. Join us to work on the Web as the platform and help create more opportunity and innovation for everyone online.

Commitment to diversity, equity, inclusion, and belonging

Mozilla understands that valuing diverse creative practices and forms of knowledge are crucial to and enrich the company’s core mission. We encourage applications from everyone, including members of all equity-seeking communities, such as (but certainly not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientation s, gender identities, and expressions.

We will ensure that qualified individuals with disabilities are provided reasonable accommodations to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment, as appropriate. Please contact us at [e-mail] to request accommodation.

We are an equal opportunity employer. We do not discriminate on the basis of race (including hairstyle and texture), religion (including religious grooming and dress practices), gender, gender identity, gender expression, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship status, military or veteran status, or any other basis covered by applicable laws. Mozilla will not tolerate discrimination or harassment based on any of these characteristics or any other unlawful behavior, conduct, or purpose.

Remote Spain