Full-Stack Software Engineer, Reinforcement Learning

Full-Stack Software Engineer, Reinforcement LearningHUD is building infrastructure to create RL training data and evals for frontier AI agents, as well as a marketplace to sell these to frontier labs through the HUD marketplace. Our platform is used by frontier labs, Fortune 500 companies, and startups. We've raised $16M from top VCs and were YC W25.We're looking for a Full-Stack Software Engineer, Reinforcement Learning to build the product surfaces, backend systems, and internal tools that power HUD's RL data engine.You'll own product surfaces end-to-end, including backend services, APIs, databases, dashboards, tools, vendor workflows, data collection, and observability for RL rollouts. You don't need to be a researcher, but you need to work research engineers and vendors to translate ambiguous needs into polished products that enable our RL systems.ResponsibilitiesDevelop product-facing tools for browsing environments, inspecting trajectories, reviewing task quality, debugging failures, and understanding model behaviorBuild vendor-facing workflows that make it easy for external partners to create, submit, test, and iterate on RL environments and training dataCreate dashboards and observability tools that surface environment quality, eval results, data collection progress, grader issues, reward signal problems, and pipeline healthDesign backend services and APIs that connect task authoring, data collection, evaluation, QA/QC, and RL training infrastructurePartner closely with research, operations, and GTM teams to turn vague, high-stakes requests into well-designed systems that ship quicklyExperienceYou may be a good fit if you have:Strong software engineering fundamentals and real full-stack range, including proficiency in Python and a modern web stack such as React, TypeScript, Next.js, or similarExperience owning user-facing or internal products end-to-endGood product taste and the ability to build tools that are intuitive for both technical and non-technical usersComfort with cloud infrastructure, Docker, CI/CD, observability, and production debuggingHigh agency—you identify what needs to exist, build it, and improve it without waiting for a perfect specStrong communication skills for working across research, engineering, operations, vendors, and foundersStrong candidates may also have:Experience building data collection, labeling, annotation, eval, or research tooling platformsExperience building dashboards, review workflows, observability tools, or debugging interfaces for complex systemsExperience building developer tools, infrastructure products, internal platforms, or workflow products that made a team dramatically fasterExperience with AWS, Kubernetes, Terraform, Docker, Grafana, or similar infrastructure tools as tools to ship product, not as the center of the roleWe prioritize technical aptitude and learning potential over years of experience. Motivated candidates are encouraged to apply even if they don't meet all criteria.Team & company detailsTeam Size: ~15 people currently, mostly full-time in-person, but some remote.Our team: Our team includes 4 International Olympiad medalists (IOI, ILO, IPhO), serial AI startup founders, and researchers with publications at ICLR, NeurIPS, etc.Company stage: We have 8 figures in funding and high revenue growth. We're scaling profitably and quickly to meet very strong demand.LogisticsEmployment: Full-time.Location: On-site only, for now. You can join the team in the San Francisco Bay Area or Singapore offices.Visa Sponsorship: We provide support for relocation and visas for strong full-time candidates to the US or Singapore.Timeline: Applications are rolling. The process is 2 technical interviews and a 2-3 day work trial.What we offerCompetitive compensation100% covered top-of-the-line medical, dental, and vision from Blue Shield of CA (US employees)Lunch and dinner when you're in the officeCompany-wide holiday break (Christmas Eve to New Year's Day) on top of PTO and paid holidaysOther perks including an Equinox membership, 401k, and commuter benefits (US employees)Unlimited* access to tokens for ChatGPT, Claude Code, Cursor, etc. * By unlimited, we mean no one on our token usage leaderboard has ever hit a limit. So we have no idea what the limit is.Due to high volume, we may not actively respond to every application, but feel free to contact us at recruiting@hud.so or elsewhere if we missed your application!