Applied AI Engineer - Contrario

Job Description Job Description Applied AI Engineer — Contrario Location: San Francisco, CA (Onsite) Compensation: $150,000 – $239,997 base + 0.2% – 0.6% equity Visa Sponsorship: H-1B, O-1, OPT supported Employment Type: Full-Time About Contrario Contrario is a high-growth YC-backed AI startup that has reached approximately $6M ARR run rate, works with 200+ venture-backed startups, and maintains 98% repeat usage. They are aggressively scaling a rapidly growing marketplace platform and hiring an Applied AI Engineer to work directly with the CTO on production AI systems. This is not a CRUD engineering role. The work centers on difficult AI product problems — marketplace intelligence, ranking systems, retrieval infrastructure, recruiter routing, automation workflows, and production AI systems. This is effectively an early core engineering hire with meaningful ownership over technical direction, product architecture, and execution speed. What You'll Own Design and implement intelligent search, retrieval, and recommendation systems powering marketplace matching Build ML-driven ranking and retrieval systems using embeddings, structured signals, behavioral marketplace data, and AI workflows Ship full-stack production features end to end across backend systems, APIs, databases, and user-facing product surfaces Develop AI-native automation workflows that accelerate sourcing, candidate evaluation, and marketplace coordination Own core infrastructure including recruiter routing, candidate evaluation pipelines, and marketplace orchestration systems Launch rapidly, collect production user feedback, and iterate quickly Partner directly with CTO on architecture, technical prioritization, and core product evolution Technical Stack Frontend: React, TypeScript, Tailwind CSS Backend: NestJS, TypeScript Database: AWS RDS (Postgres) Infrastructure: AWS ECS, AWS Fargate AI/Data: LLMs, embeddings, vector search, retrieval pipelines, AI automation systems Requirements 3+ years of meaningful AI or ML systems experience Strong TypeScript and Python proficiency Hands-on production experience with LLMs, embeddings, vector databases, retrieval pipelines, and AI workflows Experience designing APIs and working with relational databases (Postgres strongly preferred) High ownership mindset with independent execution capability Comfort operating in ambiguous startup environments without heavy direction Product-minded engineering mentality with strong UX instincts Ability to move fast and ship production systems consistently Nice to Have Experience building search, recommendation, or retrieval systems Marketplace product experience AI-native developer workflows Production LLM product feature ownership AWS deployment experience Active GitHub with strong project signal Founding engineer, CTO, or startup builder background Background from LangChain, Palantir, ByteDance, or Stripe Green Flags Strong startup execution signal Personal AI projects demonstrating curiosity and independent building Ranking/retrieval system experience Willingness to work startup intensity and hours Evidence of building outside structured work environments This Role Is NOT For Engineers looking for a traditional product or CRUD engineering role Those who need heavy direction or structured environments to operate Candidates without hands-on production AI/ML systems experience Benefits Healthcare (medical, dental, vision) Real equity ownership Gym membership / wellness stipend Flexible PTO Free lunches, dinners, snacks, and drinks Annual offsites Interview Process Pending approval Chat with CTO Technical interview Take-home project Chat with CEO Work trial (onsite) Offer Logistics Role is fully onsite in San Francisco — please only apply if you can commit to this H-1B, O-1, and OPT visa sponsorship available Shortlisted candidates will be contacted by David Joseph & Co. , the recruiting partner managing this search on behalf of Contrario.