About the role We are looking for a Senior Full-Stack Engineer to build across the whole platform: from the Go and Python services and event-driven pipelines that power it, to the React application our customers use every day.

AI is not a side project here: agents and LLM-powered workflows are core to the product, and AI-driven development is core to how we build it. You will ship features end to end, own them in production, and help raise the bar for how a modern, AI-native engineering team works.

What you'll do Build and ship product features end to end: backend services, APIs, and the React front end

Work across our Go and Python microservices

Build and evolve our React + TypeScript web application

Work with event-driven pipelines (queues, workers, schedulers) building scalable solutions

Build AI-powered product capabilities: agents, LLM integrations, and tooling

Make AI-driven development a first-class part of how you work, using coding agents and AI tooling daily, and helping shape how the team uses them well

Own quality end to end: testing, code review, observability, and deployment

Collaborate closely with Product and Design What we're looking for Must have

4+ years building and shipping production software, with senior-level ownership of features from design through operation

Strong hands-on experience with React (with TypeScript) in production applications

Strong backend experience in Go or Python (at least one is required; we work in both)

AI-driven development experience: genuine fluency with AI coding agents and assistants (e.g. Claude

Code, Cursor, Codex, etc.) as part of your real development workflow,



and sound judgement about when and how to use them

Familiarity with AI-driven development practices more broadly: working with LLMs, prompting, and evaluating AI-generated code and output critically

Solid engineering fundamentals: API design, data modelling, testing, and debugging distributed systems

Professional English, written and spoken Nice to have

Experience in both Go and Python

Familiarity with event-driven architectures: queues, workers, and asynchronous pipelines (SQS and Kafka)

Experience with AWS and its ecosystem (we also use Terraform, Docker, and Kubernetes)

Experience building AI-powered product features (tool use, MCP, RAG, evals)

Background or interest in cybersecurity

Spanish or additional languages How you work Pragmatic and product-minded: you optimise for shipping value to users, not for elegance in the abstract

Autonomous and proactive: you take a defined problem and drive it to done

Curious and fast-moving with new tools, especially AI: you experiment, adopt what works, and discard what doesn’t

Clear, direct communicator who can explain technical trade-offs to technical and non-technical audiences

High standards without preciousness: you care about quality, and you know when good enough is good enough

Comfortable operating in a fast-moving start-up environment where no two days look the same What do we offer Scope & impact: Full ownership of features across a modern, AI-native platform, with your work in front of customers from day one

Flexibility: Adaptable hours and a flexible benefits plan

Growth & team: In-house training, team-building events, and a young, energised, international team in a start-up environment

📌 Senior Full-Stack Engineer (Barcelona)
🏢 Zynap
📍 Barcelona