{"id":16529,"url":"https://alion.io/job/mercor-machine-learning-engineer-frontier-data-products","title":"Machine Learning Engineer, Frontier Data Products","company":{"id":4960,"name":"Mercor","domain":"mercor.com","url":"https://alion.io/company/mercor","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":true,"listed_via":null,"ats_vendor":"Ashby","truth_index":{"grade":"B","score":84,"open_postings":16,"ghost_share":0,"stale_share":0.438,"repost_share":0,"time_to_fill_p50_days":65,"computed_at":"2026-10-24T06:02:35Z"}},"role":"AI/ML","role_family":"AI/ML","seniority":null,"employment_type":"full_time","work_mode":"on_site","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["San Francisco, United States","New York, United States"],"countries":["US"],"hiring_countries":[],"hiring_countries_total":0,"salary":{"min":180000,"max":500000,"currency":"USD","period":"year","gross":null,"usd_annual":500000},"salary_estimate":null,"experience_years_min":null,"visa_sponsorship":false,"relocation_package":false,"has_equity":true,"technologies":[{"name":"AWS","optional":false},{"name":"Fine-tuning","optional":false},{"name":"Human-in-the-Loop","optional":false},{"name":"LiteLLM","optional":false},{"name":"LLM","optional":false},{"name":"PostgreSQL","optional":false},{"name":"Python","optional":false}],"status":"live","first_seen_at":"2026-05-29T18:20:10Z","employer_posted_date":"2026-05-29","last_verified_at":"2026-10-25T02:10:17Z","board_verified":true,"closed_at":null,"days_open":148,"trust":{"level":"ok","repost_count":0,"flags":[],"days_open":147},"description":"About Mercor\nMercor's mission is to organize human intelligence to power the AI economy. We're a leading AI data company, building the layer between human expertise and frontier models. Millions of domain experts on the platform are paid over $4 million per day to train frontier AI models. Mercor's APEX benchmark family measures AI's real-world impact on professional work. Mercor Enterprise brings this same infrastructure to Fortune 500 companies: helping companies capture how their best people actually work, translating that expertise directly back into agents.\nMercor is creating a new category of work where expertise powers AI advancement. Achieving this requires an ambitious, fast-paced and deeply committed team. You’ll work alongside researchers, operators, and AI companies at the forefront of shaping the systems that are redefining society. Mercor is a profitable Series C company valued at $10 billion. We work in-person five days a week in our San Francisco, NYC, or London offices.\nAbout the Role:\nFrontier AI companies are increasingly bottlenecked on expert judgment - capturing it reliably, validating it at scale, and turning it into durable model behavior. This role sits at the center of that problem.\nYou'll build the ML systems that power Mercor's Frontier Data Products: the infrastructure that scores, validates, and improves complex work products where correctness is rarely binary and labels are often noisy, delayed, or disputed. A single job can stay live for days, interleaving model inference, automated checks, expert review, disagreement resolution, and feedback loops. Your work determines how models reason over ambiguous inputs, when they should defer to humans, how quality is measured, and how feedback compounds into better systems over time.\nThis is applied ML product engineering under real production constraints - incomplete ground truth, shifting requirements, latency and cost tradeoffs, and workflows where a silent model failure corrupts the final output. It is not an offline benchmarks role.\nWhat You'll Do\nBuild ML systems that score, validate, and improve complex work products where correctness is nuanced and labels are imperfect.\nDesign evaluation frameworks for ambiguous tasks where ground truth is partial, delayed, or disputed.\nBuild feedback loops that turn review, disagreement, correction, and adjudication into measurable model and system improvements.\nOwn production ML behavior end-to-end: precision/recall tradeoffs, regression detection, drift, latency, cost, and explainability.\nImprove model quality using the right tool for the job - prompting, fine-tuning, retrieval, active learning, heuristics, and error analysis.\nPartner with backend engineers to integrate inference into durable, long-running workflows without sacrificing debuggability or human oversight.\nWhat Makes This Role Different\nThe architecture is not set - early engineers will define how quality is measured, how models and humans interact, where automation is trusted, and how the system compounds over time.\nThe feedback loop is short: shipping a model behavior change directly and visibly affects what customers receive.\nYou're working on a strategically central product area at Mercor at a moment when frontier AI companies have no good solution to the problem you're solving.\nDay-to-Day\nMoving fast on a young, high-ownership codebase where your decisions have long-term architectural weight.\nOperating across models, data, backend systems, and product surfaces - context switching is the default, not the exception.\nDebugging production ML failures in live, long-running workflows where silent errors matter.\nWorking closely with backend engineers on a stack of Python, Temporal, Postgres, AWS, and LiteLLM.\nBalancing automation confidence with human review - knowing when to defer is as important as knowing when to ship.\nWhat We're Looking For\nTrack record of shipping ML systems that improved a real product, workflow, or business metric.\nStrong instincts for model quality, evaluation design, error analysis, and production failure modes.\nComfort operating in ambiguous problem spaces where labels are imperfect and correctness evolves.\nSound judgment about when to reach for prompting, fine-tuning, heuristics, retrieval, human review, or a simpler product constraint.\nSolid engineering fundamentals across the full ML stack - not just modeling.\nFamiliarity with LLM applications, model-assisted workflows, evaluation frameworks, or human-in-the-loop ML is a strong plus.\nYou're likely someone who:\nDefaults to simple, inspectable ML systems that improve quickly and fail in understandable ways - not the most impressive architecture.\nGets uncomfortable when a model ships without a clear evaluation story.\nCan hold ambiguity without paralysis and make reasonable bets with incomplete information.\nCares about the real-world output of the system, not just the benchmark.\nBenefits\nBi-annual performance bonus structure.\nGenerous equity grant vested over 4 years.\nUp to $15k Relocation bonus.\n$10K housing bonus (if you live within 0.5 miles of our office).\n$1.5K monthly stipend for meals.\nFree Equinox membership.\n$200 monthly laundry reimbursement.\n$200 monthly personal wellness reimbursement.\nHealth, Dental, Vision insurance.","description_format":"text","description_chars":5282,"description_truncated":false,"requirements":{"experience_years_min":null,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":["Equity","Vision insurance"],"hiring_locations":[],"hiring_excludes":[],"relocation_offered":true,"industries":["Recruiting & Staffing","Freelance & Talent Marketplaces","AI Training Data & Annotation"],"lifecycle":[{"event":"open","at":"2026-05-29T18:20:10Z"}],"visa":[],"liveness":{"score":11,"band":"cold","label":"Long shot","p_open":1,"p_active":0.388,"p_room":0.28,"age_days":147,"expected_fill_days":65,"reasons":["conf:2","velocity","win:tail","crowd:"],"computed_at":"2026-10-24T06:02:35Z"},"pay":{"stated_usd_annual":500000,"is_top_pay":true},"html_url":"https://alion.io/job/mercor-machine-learning-engineer-frontier-data-products","json_url":"https://alion.io/job/mercor-machine-learning-engineer-frontier-data-products.json","meta":{"generated_at":"2026-10-25T04:42:24Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":6247,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-26T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":4960},"rest":"https://alion.io/mcp/rest/get_company?id=4960"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fmercor-machine-learning-engineer-frontier-data-products"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Fmercor-machine-learning-engineer-frontier-data-products"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Fmercor-machine-learning-engineer-frontier-data-products"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/mercor-machine-learning-engineer-frontier-data-products\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fmercor-machine-learning-engineer-frontier-data-products"}]}