Principal Research Engineer, AI

Summary

Join The Browser Company, a company building a better way to use the internet, as a Principal Research Engineer. You will be working on building the next LLM-powered interface for the internet, fine-tuning LLMs and smaller transformers, and optimizing model performance for on-device and cloud-based inference. You will also be collaborating with product engineers, designers, and the CTO to build and improve datasets, prototype and ship AI-powered features, and optimize inference strategies. This role requires 8+ years of experience optimizing and productionizing modern ML models, especially those running in a real-world product environment, deep experience fine-tuning open-source LLMs, and production experience with a modern coding language like Python. The Browser Company offers a competitive salary and equity package, comprehensive benefits, flexible vacation policy, remote-friendly working environment, 12 weeks of paid parental leave, and a $1,500 USD home office stipend.

Requirements

• 8+ years of experience optimizing and productionizing modern ML models, especially ones that run in a real-world product environment (bonus if you’ve worked closely with transformer models)
• You have deep experience fine-tuning open-source LLMs and going beyond simple LoRA fine-tuning
• You have production experience with a modern coding language like Python
• You're passionate about on-device performance and excited to push the boundaries of what's possible in a browser
• You have experience independently running critical projects, shipping ML features, and leading initiatives with minimal guidance
• You’re pragmatic, motivated by nebulous problems, and excited to work in a startup environment with quick product validation cycles

Responsibilities

• Fine-tune, distill, and optimize LLMs to improve performance, reduce latency, and enhance efficiency for on-device and cloud-based inference
• Improve our on-device model architecture , leveraging frameworks like MLX, ONNX, and TFLite to ensure models run efficiently across different devices
• Experiment with and integrate new LLMs , fine-tuning them for specific browser-based use cases while balancing quality, speed, and resource constraints
• Build evaluation pipelines to track model performance, accuracy, and real-world effectiveness over time
• Collaborate with product ops teams to build and improve datasets that accurately match product needs
• Collaborate with product engineers and designers to prototype and ship AI-powered features that enhance user experience
• Optimize inference strategies , including running models on-device, in the cloud, or in hybrid configurations to maximize throughput and resource usage
• Onboard to the team and codebase with your onboarding buddy
• Attend onboarding presentations about the company, product, codebase, and culture
• Get familiar with the Swift language, the Dia codebase, and how we ship features
• Ship a few bug fixes and small improvements across our codebase and tooling
• Have trained your first model, either improving an existing flow or enabling an entirely new one
• Have pair programmed with a few people on the engineering team
• Be regularly posting product feedback about the browser in our #dogfooding channel
• Be familiar with how we prototype and build new features, working with product engineers to brainstorm ways to use models to add intelligence to Dia
• Be familiar with our cloud infrastructure and data pipelines
• Be familiar with how we run inference both on-device and in the cloud
• Be testing new prototypes with existing, on-device models to test performance and viability
• Participate in product brainstorms to think about the future of Dia
• Be trained to interview candidates for roles at the Browser Company
• Be contributing to on-call rotations and jumping into incidents to support the team
• Regularly attend weekly engineering discussions about our architecture, how we do code review, code style, and more
• Collaborate with our CTO and other ML and infrastructure engineers to shape the product roadmap
• Creatively solve problems with product engineers, using pragmatic solutions ranging from basic heuristics, regressions, ML models, to AI depending on the feature
• Own our on-device model architecture, updating it to try new models, change how we work with LoRA adapters, and optimizing it for performance and quality
• Own our infrastructure to collect training data and fine-tune models for our use-cases
• Have built out mechanisms to assess quality and performance, and be working with product teams to improve the efficacy of our models and heuristics
• Drive projects from conception to production launch independently
• Be mentoring and pair-programming with newer engineers to help them get spun up on the codebase

Preferred Qualifications

We’re primarily focused on hiring in North American time zones and require that folks have 4+ hours of overlap time with team members in Eastern Time Zone

Benefits

• With our flexible compensation model, employees have the ability to choose the cash-to-equity ratio that best suits their individual needs
• Every offer we extend includes three options: a salary-optimized offer, an equity-optimized offer, and a balanced offer
• The annual salary range for this role is $250,000 - $330,000 USD
• The actual salary range offered will vary based on experience level and interview performance
• Comprehensive benefits package with employee medical, dental, and vision - we cover 100% of premiums for employees, and up to 95% for dependents
• 401k plan
• Flexible vacation policy - on average, our team members take between 15-20 vacation days a year, plus federal holidays (holidays vary by location)
• Remote-friendly working environment - our core working hours are 11 AM-2 PM Eastern Time
• 12 weeks of paid parental leave
• Employees based in the US also receive additional services like free annual memberships to One Medical (where available), Talkspace, Teladoc, and HealthAdvocate
• We are a remote-first, distributed team, with the option to work from office in Brooklyn, New York