As part of AI-LAB as a Full-Stack Developer, you will be instrumental in building and scaling our AI products. You will own features end-to-end across a modern Next.js frontend and our NestJS backend services, delivering a seamless and powerful user experience. You'll be joining a team with a ship-fast mindset and a modern, carefully curated tech stack.

Develop and maintain features on our Next.js (App Router) frontend using TypeScript, SWR, Tailwind, and a component-driven design system, with full internationalization (i18n) support.
Design, implement, and maintain RESTful APIs with NestJS (TypeScript) to manage authentication, data processing, billing, usage tracking, and orchestration of AI workflows.
Own backend services end-to-end: from schema design and migrations to deployment and observability, and contribute to new services as the product surface grows.
Integrate and maintain third-party SDKs and APIs that power critical product flows, including payment processing, authentication, analytics, and messaging.




Build AI agents and tools using the Claude SDK and Model Context Protocol (MCP): giving LLMs real-time access to data, APIs, and tools so they can take meaningful actions on behalf of users.
Contribute to schema design with Prisma and PostgreSQL, write and review migrations, and reason carefully about data models that evolve safely over time.
Implement and maintain feature flags, A/B experiments, and analytics events so product decisions are driven by data.
Handle incoming webhooks and asynchronous task processing with the rigor required for payment-critical and PII-handling code paths (idempotency, retries, fault tolerance).
Collaborate with AI product managers and AI specialists to translate complex requirements into robust, scalable features — and push back on complexity when a simpler path exists.
Collaborate on application deployment and help maintain our cloud infrastructure.

Requirements

We are seeking a proactive and skilled developer who is pa

📌 AI Full Stack Developer (Barcelona)
🏢 Leadtech Group
📍 Barcelona