Job Details

FERMÀT is the AI native commerce platform that optimizes shopping experiences, leading to best-in-class shopper engagement and conversion. We help brands transform clicks into conversions with dynamic, personalized shopping experiences-built and optimized in minutes.

Backed by VMG, Bain Capital Ventures, Greylock, QED, and named The Information's #1 commerce startup, we're a 70+ person team based in SF, Austin, NYC, and Bangalore. As a fast-growing Series B company, we're building the infrastructure for the future of online retail-and we're just getting started.
About the Role:

We're searching for a productminded Software Engineer to help build out Pierre, FERMÀT's AI Agent, into a productiongrade intelligence engine that powers personalization, automation, and operational insights across our commerce platform. You will design and build LLMpowered features endtoend: orchestration (tools/agents/functioncalling), retrieval, evaluations and productionization (APIs, observability, cost/latency). If you love turning ambiguous problems into shipped experiences-and you have experience taking AI products to market in the last 12 to 18 months, this role is for you.
What You'll Work On:

• Take AI products to market: prototype quickly, instrument, A/B test, and iterate based on quality, conversion impact, latency, and cost.
• Own LLM orchestration: multi-agent systems, tool use, functioncalling, structured outputs, routing, context windows, retrieval and evals.
• Build evaluation & observability: golden datasets, automated evals, prompt/version management and monitoring.
• Productionize reliably: scalable APIs/services, workers/queues, caching and provider failover. Optimize performance while keeping costs reasonable.
• Data foundations: integrate firstparty events and catalog data; respect data contracts.
• Vendor strategy: evaluate and integrate multiple model providers (e.g., OpenAI, Anthropic, Google) while tracking quality, cost, and reliability.
• Raise the bar: document best practices, lead design reviews, and mentor engineers on AI patterns.

• 4+ years of professional software engineering experience.
• 12-18 months building and shipping LLMpowered products (from prototype to GA) with meaningful customer adoption. Please include links, demos, or a brief writeup if possible.
• Strong Python and TypeScript experience. Solid systems design and API fundamentals.
• Handson with LLM APIs, embeddings, vector databases, retrieval patterns and agent/tool design.
• Pragmatic prompt engineering and prompt/version control
• Production chops: cloud (GCP), containers, CI/CD, monitoring/alerting; comfort owning services in prod.
• Product sense, clear communication, and a bias to ship.

• Ecommerce, recommendations, ranking or ads experience.
• Experience with streaming responses, Streamable HTTP/SSE/WebSocket patterns for real-time AI interactions.
• Realtime personalization and event pipelines (e.g., Kafka, pub/sub).
• Frontend (React) skills for rapid prototyping of AI UX.
• Experimentation/analytics tools (e.g., PostHog or similar).

• Competitive salary + equity package
• Comprehensive health, dental, and vision insurance for you and all your dependents.
• Retirement benefits:
  
  • US: 401(k) plan with 4% matching
  • India: Provident Fund with 12% matching
• 4 months of paid parental leave
• Unlimited PTO policy (with minimum 5 days PTO / quarter!)