Senior Full Stack Developer, AI

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

📋 Description

• As a Full-Stack Developer in the Development team, you will play a vital role in constructing and expanding our platforms and products.

• You will engage with our entire A.I technology stack to provide a seamless and robust user experience.

• You will be involved in projects that adopt a rapid shipping approach and utilize a modern tech stack.

• Design, implement, and maintain RESTful APIs using NextJS/Express for managing user authentication, data processing, and orchestrating analysis workflows.

• Model Context Protocol (MCP) Knowledge Agents with Claude SDK: to create AI agents that access real-time data, APIs, and tools, allowing them to perform actions by combining the reasoning capabilities of LLMs with real-world integration.

• Develop AI Agents using LangGraph + LangFuse that can perform multi-step reasoning, create workflows where AI agents collaborate or delegate tasks to other agents, maintain conversation state and context throughout interactions, and manage complex decision trees and conditional logic.

• Enhance and sustain features on both our React frontend and Node.js (NextJS) backend.

• Construct intuitive user interfaces employing TypeScript, Vite, React, and our UI component library, enabling users to upload media, manage analyses, and engage with our web-delivered product.

• Integrate our platform with various external services such as Payment Service Providers and APIs, and manage incoming webhooks for processing asynchronous tasks.

• Work in close collaboration with AI product managers and AI specialists to convert complex requirements into robust, scalable features represented in AI design prompts.

• Contribute to the design of the database schema and develop migrations for our PostgreSQL & BigQuery databases.

• Possess knowledge of GCP to collaborate with the team on application deployment and assist in maintaining our cloud infrastructure on Google Cloud Platform.

⛳️ Requirements

• Extensive experience with the Python framework.

• In-depth API Integration expertise with third-party vendors, capable of swiftly integrating various types of SDKs into our products.

• A dedicated self-learner who adapts quickly to new tools and platforms, incorporating them into daily workflows in a matter of days.

• Proficiency in TypeScript: Highly skilled in TypeScript and its application in both frontend (React) and backend (Node.js) environments.

• Frontend Expertise: Strong background in React and modern state management, including Hooks and the Context API.

• Backend Expertise: Solid experience in building and consuming REST APIs using Node.js and NextJS or Express.

• Database Skills: Familiarity with PostgreSQL and experience working with an ORM or query builder.

• Knowledge of LangGraph, LangChain, and LangFuse.

• Problem-Solving Mindset: A collaborative problem-solver eager to tackle new challenges and contribute to a fast-paced development cycle.

• Passion for AI: A genuine enthusiasm and awareness of artificial intelligence, with a strong desire to develop products that utilize its capabilities to address real-world issues and enhance our product portfolio.

• High Agency: In consultation with a Product Owner and the Engineering Manager, you will operate autonomously with considerable freedom to realize the business vision.

• Creativity and Proactivity: You have a passion for creating outstanding products, are eager to propose new features, and enjoy discovering innovative solutions to enhance the user experience.

• Nice to Have: Previous experience in projects related to AI, machine learning, or working with large language models (LLMs).

• Familiarity with UI component libraries.

• Knowledge of cloud platforms such as Google Cloud Platform (GCP).

🏝️ Benefits

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

• Modern Technology: Utilize a cutting-edge, carefully selected tech stack with a focus on best practices.

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

• Stability & Vision: Experience 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 enthusiasm for creating exceptional products.

• Growth and Career Development: At Leadtech, your growth is our priority. Enjoy 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 option to work fully remotely 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: Receive a 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!

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

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