AI Full Stack Developer

This is a fully remote position, open to applicants in Spain.

📋 Description

• Develop and sustain features on our Next.js (App Router) frontend utilizing TypeScript, SWR, Tailwind, and a component-driven design system, ensuring full internationalization (i18n) support.

• Design, implement, and manage RESTful APIs with NestJS (TypeScript) to handle authentication, data processing, billing, usage tracking, and orchestration of AI workflows.

• Take ownership of backend services from start to finish: including schema design, migrations, deployment, and observability, while contributing to new services as the product expands.

• Integrate and oversee third-party SDKs and APIs that facilitate essential product functionalities, such as payment processing, authentication, analytics, and messaging.

• Develop AI agents and tools using the Claude SDK and Model Context Protocol (MCP), providing LLMs with real-time access to data, APIs, and tools to enable meaningful user actions.

• Participate in schema design using Prisma and PostgreSQL, write and review migrations, and thoughtfully consider data models that can evolve safely over time.

• Implement and manage feature flags, A/B testing, and analytics events to ensure that product decisions are data-driven.

• Process incoming webhooks and manage asynchronous task processing with the precision required for payment-critical and PII-handling code paths (idempotency, retries, fault tolerance).

• Work alongside AI product managers and AI specialists to convert complex requirements into robust, scalable features while advocating for simplicity when feasible.

• Collaborate on application deployment and assist in maintaining our cloud infrastructure.

⛳️ Requirements

• TypeScript Proficiency: Highly skilled in TypeScript for both frontend (React/Next.js) and backend (Node.js/NestJS) environments.

• Frontend Expertise: Extensive experience with React and Next.js (App Router), including Server Components, route handlers, streaming, metadata, i18n, and modern data-fetching patterns (SWR or equivalent).

• Backend Expertise: Strong experience in building production REST APIs with NestJS (or similar Node frameworks like Express/Fastify), including modules, DI, guards, interceptors, and DTO validation.

• Database Skills: Proficient in PostgreSQL and an ORM such as Prisma, comfortable with writing and reviewing migrations, understanding transactions, and designing schemas that evolve safely.

• API Integration Depth: Proven experience in integrating third-party SDKs, managing webhooks, idempotency, retries, and asynchronous fulfillment.

• Problem-Solving Mindset: Collaborative and pragmatic, willing to challenge assumptions and highlight trade-offs before coding.

• Passion for AI and High Agency: Genuine enthusiasm for AI products and a proactive desire to introduce new techniques and tools to the team.

• Creativity and Proactivity: Enjoys proposing features, discovering innovative solutions, and enhancing user experience without needing direction.

• A committed self-learner who swiftly adapts to new tools and platforms in days rather than weeks.

🏝️ Benefits

• High-Impact Role: Be an integral part of a small, agile team working on greenfield projects with the potential to revolutionize an industry.

• Modern Technology: Engage with a state-of-the-art, thoughtfully chosen tech stack that emphasizes best practices.

• Growth & Learning: Acquire extensive experience in AI-driven applications, cloud-native architecture, and real-time systems.

• Stability & Vision: Enjoy the dynamic environment of a startup supported by the resources and stability of a large, successful company.

• Collaborative Culture: We prioritize open communication, teamwork, and a shared passion for creating exceptional products.

• Growth and career development: At Leadtech, your growth is our priority. Experience a flexible career path with personalized internal training and an annual budget for external learning opportunities.

• Work-Life balance: Benefit from a flexible schedule with flextime and the choice to work fully remote or from our Barcelona office. Enjoy free Friday afternoons with a 7-hour workday, plus a 35-hour workweek in July and August to relish summer!

• Comprehensive benefits: Competitive salary, full-time permanent contract, and premium private health insurance (including dental and psychological services).

• 25 days of vacation plus your birthday off, with flexible vacation options—no blackout days!

• Unique Perks: If you choose to work from our office in Barcelona, enjoy complimentary coffee, fresh fruit, snacks, a game room, and a rooftop terrace with breathtaking Mediterranean views.

• Additional benefits include meal tickets and nursery vouchers, paid directly from your gross salary.