AI Full Stack Developer

Job not on LinkedIn

🕒 July 27

🇪🇸 Spain – Remote

⏰ Full Time

🟡 Mid-level

🟠 Senior

🧑‍💻 Full-stack Engineer

👻 Ghost score 24%

What it means: how likely this posting is sitting open without active hiring.How to read it: 60% or higher means we think this is a ghost. Lower scores are less of a worry.How we score it: age, reposts, open roles vs team size, how fast jobs close, and whether pay is listed.Fine print: an estimate from public data, not a judgment of the company. Real jobs can score high, so treat it as a hint, not a fact.

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LEADtech

WebsiteLinkedInAll Job Openings

2 - 10 employees

Founded 2017

🛍️ eCommerce

🛒 Retail

🔧 Hardware

eCommerce • Retail • Hardware

LEADtech is an online Romanian retailer and e‑commerce store that offers a broad catalogue of consumer electronics, IT and computer components, mobile phones, home electronics, gaming gear, appliances, tools, garden equipment, baby products and smart home/security devices. The site content (Romanian language, references to "lei" and sections like "Contul Meu") indicates a web storefront selling products from stock with delivery, account/returns support, and extensive category-based merchandising for consumers and small businesses.

📋 Description

• 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. • 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

• TypeScript Proficiency: Highly proficient in TypeScript across both frontend (React/Next.js) and backend (Node.js/NestJS) environments. • Frontend Expertise: Strong experience with React and Next.js (App Router): Server Components, route handlers, streaming, metadata, i18n, and modern data-fetching patterns (SWR or equivalent). • Backend Expertise: Solid experience building production REST APIs with NestJS (or comparable Node frameworks like Express/Fastify): modules, DI, guards, interceptors, DTO validation. • Database Skills: Experience with PostgreSQL and an ORM such as Prisma. Comfortable writing and reviewing migrations, reasoning about transactions, and designing schemas that evolve safely. • API Integration Depth: Real experience integrating third-party SDKs: handling webhooks, idempotency, retries, and asynchronous fulfillment. • Problem-Solving Mindset: Collaborative, pragmatic, willing to challenge assumptions and surface tradeoffs before writing code. • Passion for AI and High Agency: Genuine enthusiasm for AI products, and a desire to bring new techniques and tools into the team proactively. • Creativity and Proactivity: You enjoy proposing features, finding creative solutions, and improving the user experience without being told to. A serious self-learner who adapts to new tools and platforms in days, not weeks. • Nice to Have: Prior experience working on payment/subscription systems. Familiarity with monorepo tooling (pnpm workspaces, Turborepo, Nx). Experience with BigQuery and event-pipeline analytics. Familiarity with Tailwind and component-driven design systems. Knowledge of cloud platforms such as Google Cloud Platform (GCP). Experience with feature-flag systems. Previous work on AI products or LLM-powered applications.

🏖️ Benefits

• Competitive salary, full-time permanent contract, and top-tier private health insurance (including dental and psychological services). • 25 days of vacation plus your birthday off, with flexible vacation options—no blackout days! • Work-life balance: Benefit from a flexible schedule with flextime and the option of working 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 so you can savor summer! • Growth and career development: At Leadtech, we prioritize your growth. Enjoy a flexible career path with personalized internal training and an annual budget for external learning opportunities. • Unique Perks: Office in Barcelona equipped with free coffee, fresh fruit, snacks, game room, and rooftop terrace with stunning Mediterranean views.