Junior Software Engineer jobs in United States

Remote UK

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.

Are you enthusiastic about optimizing software that millions of people rely on every day? Do you enjoy the challenge of debugging complex multi-threaded C++ code? Are you excited about web technologies and the applications built on them that enrich users’ lives? If so, we’d love to hear from you!

• Improve Storage, Workers and system-level surfaces of our Web engine, with a strong focus on performance, stability and security
• Develop and debug in a large, complex, multi-threaded, and multi-process codebase
• Develop and debug across multiple platforms
• Investigate issues and propose solutions and architectural improvements
• Drive features and projects from start to completion
• Read and implement API specifications, and contribute to the standards process
• Collaborate with the widespread Firefox team on shared goals

• Proficiency in C++
• Deep experience with multi-threaded, multi-process codebases, including work on performance‑critical, sandboxed or storage architectures
• Cross‑platform development experience with native applications (desktop and mobile)
• Proven ability to deliver maintainable solutions in large, evolving codebases
• Strong problem‑solving skills, able to diagnose complex issues without clear logs or reliable reproduction steps
• Great written communication skills and ability to lead discussions effectively, both in writing and verbally
• Commitment to our values:
• Being relationship‑minded
• Having grit

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.

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 hiringaccommodation@mozilla.com 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 UK