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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Full Stack Engineer (Los Altos) - **Company:** Cheiron - **Location:** León, Spain - **Contract:** Permanent contract - **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Databases, Graph Database, Python (Programming Language), PostgreSQL, Search Technologies, TypeScript, ReactJS, Large Language Models, Multi-Agent Systems, Indexer, Backend, Fastapi, Build Management, Build Tools, Front End Software Development, Api Design, Automation Anywhere - **Published:** September 15, 2026 - **Apply:** https://www.buscojobs.com.es/full-stack-engineer-los-altos-en-leon-ID-370766757 ## About the Role We're looking for a hands?on builder who can quickly structure ambiguous problems and turn them into highly polished products. You don't need to be an AI researcher or a life sciences domain expert, but we care deeply about strong engineering fundamentals and real experience designing, building, and operating LLM systems.What You'll Do- Design and build backend services on Python, FastAPI, and Postgres- Build applied AI workflows using the OpenAI API, LangGraph, vector DBs, and search systems- Develop ingestion, indexing, and search pipelines for life sciences data, including academic papers, clinical, regulatory, safety, and patent sources- Build customer-facing features end to end, from the data model to the API to the React/TypeScript frontend- Build systems that ground AI-generated outputs in source data with traceable, verifiable citations so they can be trusted in real pharma and biotech work- Work directly with founders, domain experts, and early customers, owning outcomes rather than just closing ticketsRequirements- 2+ years of experience shipping production software end to end- Strong backend engineering fundamentals and experience designing APIs, databases, and services- Hands?on production experience with AI?driven systems such as LLMs, agents, RAG, and vector DBs- Full-stack range, comfortable working through the frontend with React and TypeScript- The drive to set your own priorities and ship quickly, even when specs are incomplete- Active use of AI coding tools such as Claude Code and CursorNice to Have- Hands?on experience designing and operating LangGraph, agent frameworks, or RAG systems in production- Experience with vector DBs, semantic search, and knowledge graphs- Experience building enterprise SaaS, or pharma, biotech, or healthcare products- Familiarity with life sciences domain data such as academic literature, clinical trials, regulatory documents, and patents- Experience at a seed or early-stage startupBenefits & Perks- 401(K) retirement plan- Health insurances (Medical/Dental/Vision)- Meal allowance (Lunch, Dinner)- Transportation support for early starts and late nights- In?office snack bar and additional commuting and work travel support#J-*****-Ljbffr ## Description Company OverviewCheiron is a Stanford-founded AI company building an AI-native operating system for the pharma, biotech, and broader life sciences industry.Since launching in ****, we've rapidly grown our global user base.In Korea, we reached 22% of industry users within six months and are now used across 200+ pharma and biotech companies as we continue to scale quickly.About the RoleWe're looking for a Full Stack Engineer, Applied AI to help build Cheiron's core product and infrastructure.This role spans the full stack - backend systems, AI workflows, RAG and search pipelines, APIs, and the customer-facing product itself.You won't own just one slice; you'll work deeply across the product and systems and solve whatever problems need solving.We build products that run in real customer environments - not research demos or prototypes.We're looking for a hands?on builder who can quickly structure ambiguous problems and turn them into highly polished products.You don't need to be an AI researcher or a life sciences domain expert, but we care deeply about strong engineering fundamentals and real experience designing, building, and operating LLM systems.What You'll Do- Design and build backend services on Python, FastAPI, and Postgres- Build applied AI workflows using the OpenAI API, LangGraph, vector DBs, and search systems- Develop ingestion, indexing, and search pipelines for life sciences data, including academic papers, clinical, regulatory, safety, and patent sources- Build customer-facing features end to end, from the data model to the API to the React/TypeScript frontend- Build systems that ground AI-generated outputs in source data with traceable, verifiable citations so they can be trusted in real pharma and biotech work- Work directly with founders, domain experts, and early customers, owning outcomes rather than just closing ticketsRequirements- 2+ years of experience shipping production software end to end- Strong backend engineering fundamentals and experience designing APIs, databases, and services- Hands?on production experience with AI?driven systems such as LLMs, agents, RAG, and vector DBs- Full-stack range, comfortable working through the frontend with React and TypeScript- The drive to set your own priorities and ship quickly, even when specs are incomplete- Active use of AI coding tools such as Claude Code and CursorNice to Have- Hands?on experience designing and operating LangGraph, agent frameworks, or RAG systems in production- Experience with vector DBs, semantic search, and knowledge graphs- Experience building enterprise SaaS, or pharma, biotech, or healthcare products- Familiarity with life sciences domain data such as academic literature, clinical trials, regulatory documents, and patents- Experience at a seed or early-stage startupBenefits & Perks- 401(K) retirement plan- Health insurances (Medical/Dental/Vision)- Meal allowance (Lunch, Dinner)- Transportation support for early starts and late nights- In?office snack bar and additional commuting and work travel support#J-*****-Ljbffr ## Related Videos - [Developing the Backend with Stefan Lingler, CTO at Shpock](https://www.wearedevelopers.com/videos/100360-developing-the-backend-with-stefan-lingler-cto-at-shpock) - [Optimizing Discovery: PostgreSQL's Role in Transforming GetYourGuide's Search](https://www.wearedevelopers.com/videos/1647-optimizing-discovery-postgresql-s-role-in-transforming-getyourguide-s-search) - [Watch Tests Go Brrrr! : Getting Started with Cypress in ReactJS](https://www.wearedevelopers.com/videos/282-watch-tests-go-brrrr-getting-started-with-cypress-in-reactjs) - [Shipping Faster with Less: Render on Cloud Hosting, AI Workloads, and the Future of DevOps](https://www.wearedevelopers.com/videos/1894-shipping-faster-with-less-render-on-cloud-hosting-ai-workloads-and-the-future-of-devops) - [Nest.js - TypeScript in the backend can also be clean](https://www.wearedevelopers.com/videos/1033-nest-js-typescript-in-the-backend-can-also-be-clean) - [Dynamic Entities in .NET: Building Low-Code Systems on Top of Entity Framework Core](https://www.wearedevelopers.com/videos/100218-dynamic-entities-in-net-building-low-code-systems-on-top-of-entity-framework-core) ## Related Articles - [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline) - [Dev Digest 137 - AI'm not sure about this](https://www.wearedevelopers.com/magazine/485-dev-digest-137-ai-m-not-sure-about-this) - [Dev Digest 132 - Binging WADFlix?](https://www.wearedevelopers.com/magazine/473-dev-digest-132-binging-wadflix) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [How to Become an AI Engineer](https://www.wearedevelopers.com/magazine/331-how-to-become-an-ai-engineer) - [What Are Large Language Models?](https://www.wearedevelopers.com/magazine/304-what-are-large-language-models)