Sr. Staff Software Engineer, Browser (New Products) New Remote US

Applying; Northern (KY); Remote; USD 166,000 - 260,000; Full time

Benefits offered by this job

Performance bonus

Medical, dental, vision

Retirement contributions

Wellness days

Holidays

Home office stipend

Well-being stipend

Parental leave

Referral bonus

Other benefits

Job summary

Mozilla Corporation is seeking engineers to prototype engine features enabling reliable programmatic interaction with web content. You will profile overhead and pursue data-driven improvements, using AI tools to speed coding while validating results through debugging, tests, and measurement.

The role emphasizes investigating unfamiliar code, grounding performance claims in reproducible evidence, and exploring how agent harnesses affect information flow and tasks.

Qualifications

• Ability to investigate unfamiliar code and form precise hypotheses.
• Experience with profiling, tracing, and reproducible testing.
• Curiosity about AI agents and debugging with tooling.

Responsibilities

• Prototype engine capabilities for interacting with web content.
• Profile overhead of new capabilities and measure improvements.
• Use AI tools to accelerate coding and verify via tests and measurements.

Skills

Code analysis

Profiling

AI tooling

Job description

Remote US

Why Mozilla?

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

What you'll do:

• Prototype engine capabilities that support reliable programmatic interaction with web content. Investigate how document structure, layout, navigation, and event handling affect correctness and performance.
• Profile the overhead introduced by new capabilities and pursue improvements where measurements justify them. Use AI tools to accelerate coding and analysis, and verify their output through debugging, tests, and measurement.

What you'll bring:

• A demonstrated ability to investigate unfamiliar code, form a precise hypothesis, construct a useful prototype, and interpret the results. You can separate the effects of your implementation from variability in websites, workloads, or model behavior.
• Experience with profiling, tracing, regression tests, or conformance tests, and a habit of grounding performance claims in reproducible evidence. You can explain both the benefit of an optimization and the circumstances in which it fails.
• Curiosity about AI agents and a willingness to work directly with agent harnesses and coding tools. You can connect a low-level implementation choice to the information an agent receives and the work it must do next.

Nice to have:

• Experience maintaining an open-source project
• Technical leadership in a small team building a new product

What you’ll get:

• Generous performance-based bonus plans to all eligible employees - we share in our success as one team
• Rich medical, dental, and vision coverage
• 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
• 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.

Group: C

#LI-REMOTE

Hiring Ranges:

$195,000 - $260,000 USD

$179,000 - $239,000 USD

$166,000 - $221,000 USD

USA Demographic Questions

At Mozilla we value diversity, prioritize equity and inclusion, and proactively work to design hiring processes that mitigate bias. 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.

To help us track the effectiveness of these efforts, please consider answering the following demographic questions. Answering these questions is entirely voluntary. Your decision to respond (or not) won't be considered in the hiring process or thereafter. Any information you do provide will have no impact on the hiring process. Should you become a Mozilla employee, the information provided will not be transferred to your employee profile. In addition, the information you provide will be aggregated and dis-identified, ensuring that your responses cannot be traced back to you personally by Mozilla.

Voluntary Self-Identification of Disability

How do you know if you have a disability?

You are considered to have a disability if you have a physical or mental impairment or medical condition that substantially limits a major life activity, or if you have a history or record of such an impairment or medical condition.

Disabilities include, but are not limited to:

• Autism
• Autoimmune disorder, for example, lupus, fibromyalgia, rheumatoid arthritis, or HIV/AIDS
• Blind or low vision
• Cancer
• Cardiovascular or heart disease
• Celiac disease
• Cerebral palsy
• Deaf or hard of hearing
• Depression or anxiety
• Diabetes
• Epilepsy
• Gastrointestinal disorders, for example, Crohn's Disease, or irritable bowel syndrome
• Missing limbs or partially missing limbs
• Nervous system condition for example, migraine headaches, Parkinson’s disease, or Multiple sclerosis (MS)
• Psychiatric condition, for example, bipolar disorder, schizophrenia, PTSD, or major depression