Fullstack Developer

Alstech
Boiro, Spain
yesterday

Role details

Contract type
Permanent contract
Employment type
Full-time (> 32 hours)
Working hours
Regular working hours
Languages
English
Compensation
€ 60K

Job location

Boiro, Spain

Tech stack

Artificial Intelligence
Software Applications
Web Scraping
Cursor (Graphical User Interface Elements)
Database Design
Software Debugging
Python
Performance Tuning
Systems Integration
TypeScript
Reinforcement Learning
React
Large Language Models
Backend
FastAPI
Production Code
Front End Software Development
Asynchronous Programming
REST
Data Pipelines

Job description

Alstech is seeking a talented full-stack engineer in O Chazo, Spain, to build and enhance infrastructure for reinforcement learning environments. You'll play a vital role in transforming concepts into production-ready applications while collaborating closely with founders and researchers., Frontend development with React Backend development with Python, FastAPI Database design and implementation System design and debugging Writing clean, scalable code Descripción del empleo About the Opportunity

We're partnering with a stealth AI company building infrastructure that powers reinforcement learning (RL) environments for some of the world's leading AI labs. Their systems operate directly within the AI training loop, helping evaluate, improve, and deploy next-generation AI models. This is highly applied, production-focused engineering work with real-world impact. What You'll Do

  • Build full-stack applications end-to-end (frontend, backend, and infrastructure)
  • Transform loosely defined concepts into production-ready products
  • Design and implement systems supporting AI agents and RL workflows
  • Deliver high-quality software rapidly without sacrificing maintainability
  • Collaborate directly with founders, researchers, and engineering leadership
  • Own projects from specification to deployment with minimal oversight

How You'll Work

  • Operate with a high degree of autonomy and ownership
  • Use modern AI coding tools (Cursor, Claude Code, Codex, etc.) to accelerate development
  • Review and validate all AI-generated code
  • Make architectural decisions independently
  • Work primarily through asynchronous communication (Slack)
  • Move quickly while maintaining engineering excellence

Requirements

The ideal candidate has strong experience with React and Python, alongside a good grasp of system design and database implementation. This is an opportunity to work in an AI-driven environment, offering high autonomy and impactful projects., * Strong experience building and shipping complete software products.

  • Experience with modern UI frameworks and REST APIs.
  • Ability to write production-quality code., Core Technical Skills
  • Strong experience building and shipping complete software products
  • Frontend development with: React, TypeScript, modern UI frameworks
  • Backend development with: Python, FastAPI, REST APIs & integrations
  • Database design and implementation
  • System design, debugging, and performance optimization
  • Writing clean, scalable, production-quality code

Nice to Have

  • Experience with LLMs, AI agents, or AI-powered applications
  • Experience building data pipelines or web scraping systems
  • Startup, freelance, or rapid-delivery environment experie

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