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# Founding Full Stack Engineer - €70.000 A Year

- **Company:** Equator
- **Location:** Madrid, Spain
- **Salary:** €70,000.0
- **Contract:** Permanent contract
- **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Data Systems, Graph Database, Python (Programming Language), Knowledge Management, PostgreSQL, Software Architecture, Next.js, Software Engineering, TypeScript, Management of Software Versions, Web Application Frameworks, Tailwind, ReactJS, Large Language Models, Backend, Front End Software Development
- **Published:** July 28, 2026
- **Apply:** https://www.buscojobs.com.es/founding-full-stack-engineer-%E2%82%AC-70-000-a-year-en-madrid-ID-364755670

## About the Role

You will collaborate directly with the founders and play a key role in designing the technical foundation for an AI-native product serving complex biopharma workflows.Key Responsibilities:Architect scalable, auditable backend systems (Python, PostgreSQL, modern frameworks)Build APIs enabling seamless collaboration between humans and AI agentsDevelop clean, modular frontend interfaces using React, Next.Js, and TypeScriptImplement and maintain data-heavy systems and structured knowledge frameworksWrite clean, precise code and contribute to strong engineering standardsCollaborate closely with founders, designers, and early users to deliver impactful featuresInfluence product, technical direction, and architectural decisions as a founding engineerRequired Qualifications:4-6 years of software engineering experience (mid to senior level)Strong backend engineering skills withPythonProficiency in React, Next.Js, TypeScript, Node.JsExperience building data-heavy or versioned backend systemsStrong
clean-code discipline and architectural thinkingEnglish (Advanced/C1+)Valid Spain work permit (no sponsorship available)Nice-to-Have Skills:Experience with AI agents or LLM-native applicationsKnowledge of Supabase, Postgres, RLS, versioning systemsFamiliarity with Radix, Tailwind, shadcn/ui, Inngest, Modal, ZodEngineering degree; PhD is a plusBackground in life sciences, biopharma, or complex scientific domainsWhat Equator Offers:Opportunity to join as one of the first engineers and shape the product from day oneHigh-impact work solving real problems for biopharma teamsA collaborative culture that values in-person interactionHybrid model with strong preference for onsite work in the Barcelona office#J-*****-Ljbffr

## Description

Job Title:Founding Full-Stack Software Engineer - AI for BiopharmaLocation:Barcelona, SpainEmployment Type:Full-timeCompensation & Benefits:From €70,000Gym membershipHybrid model, but with regular onsite collaboration strongly preferredAbout the Company:Equator is a newly founded AI-native startup building next-generation software for the biopharma industry.Their mission is to solve one of the sector's biggest challenges: knowledge management across scientific, commercial, and operational teams.Equator's platform uses AI agents, knowledge graphs, and structured data systems to help biopharma organizations understand, compare, and act on their internal information.The result is a smarter, more proactive way for teams to collaborate and make decisions.This is an early-stage, senior, fast-moving environment where you'll help shape the product, architecture, and engineering culture from the very beginning.Job Summary:As a Founding Full-Stack Engineer, you will build core product features end-to-end across backend and frontend.You will collaborate directly with the founders and play a key role in designing the technical foundation for an AI-native product serving complex biopharma workflows.Key Responsibilities:Architect scalable, auditable backend systems (Python, PostgreSQL, modern frameworks)Build APIs enabling seamless collaboration between humans and AI agentsDevelop clean, modular frontend interfaces using React, Next.Js, and TypeScriptImplement and maintain data-heavy systems and structured knowledge frameworksWrite clean, precise code and contribute to strong engineering standardsCollaborate closely with founders, designers, and early users to deliver impactful featuresInfluence product, technical direction, and architectural decisions as a founding engineerRequired Qualifications:4-6 years of software engineering experience (mid to senior level)Strong backend engineering skills withPythonProficiency in React, Next.Js, TypeScript, Node.JsExperience building data-heavy or versioned backend systemsStrong clean-code discipline and architectural thinkingEnglish (Advanced/C1+)Valid Spain work permit (no sponsorship available)Nice-to-Have Skills:Experience with AI agents or LLM-native applicationsKnowledge of Supabase, Postgres, RLS, versioning systemsFamiliarity with Radix, Tailwind, shadcn/ui, Inngest, Modal, ZodEngineering degree; PhD is a plusBackground in life sciences, biopharma, or complex scientific domainsWhat Equator Offers:Opportunity to join as one of the first engineers and shape the product from day oneHigh-impact work solving real problems for biopharma teamsA collaborative culture that values in-person interactionHybrid model with strong preference for onsite work in the Barcelona office#J-*****-Ljbffr


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