Senior Full Stack Software Engineer (Python, React), Remote, Madrid/Barcelona

Help build high-performance web applications used by thousands of users.

We’re looking for a Senior Full Stack Software Engineer with a strong backend focus in Python and solid React experience to help design and scale modern web applications. This role is ideal for someone who enjoys solving complex engineering challenges, making architectural decisions, and building systems designed for reliability and performance at scale.

You’ll work closely with engineers and stakeholders to deliver robust, user-friendly applications while contributing to both backend architecture and modern frontend improvements.

About the Role

As a Senior Full Stack Engineer , you will play a key role in shaping the technical direction of the platform. You’ll lead backend architecture decisions, build scalable services, and help evolve the frontend experience using modern technologies.

The platform supports thousands of concurrent users and high-frequency external integrations , so performance, stability, and scalability are critical.

You’ll also help drive engineering best practices, improve testing coverage, and contribute to continuous technical improvements across the stack.

What You’ll Be Doing

• Leading the design and development of backend services using Python
• Building scalable APIs and services capable of supporting high traffic and concurrent users
• Contributing to modern frontend development using React and TypeScript
• Making key architectural and technical decisions
• Improving system performance, reliability, and scalability
• Writing well-tested backend and frontend code
• Implementing end-to-end and integration testing using Playwright
• Collaborating with engineers and stakeholders to deliver high-quality solutions
• Supporting ongoing technology improvements and engineering best practices

What We’re Looking For

• Solid professional background developing backend services with Python
• Several years of experience working with JavaScript for web applications , ideally using React
• Proven track record building scalable web platforms and API-driven applications
• Experience designing systems that prioritise stability, efficiency, and high performance
• Strong understanding of modern backend design patterns and scalable architectures
• Hands-on experience implementing automated testing and maintaining reliable codebases
• Confidence in contributing to architectural discussions and influencing technical direction

Experience with technologies such as:

Python, FastAPI, ReactJS, TypeScript, Tailwind, Vite

Redis, MongoDB, PostgreSQL, Alembic

Docker, Kubernetes, Azure DevOps, AWS

Experience with infrastructure or DevOps practices is a plus , but not mandatory as deployments and operations are handled by a dedicated infrastructure team.

Additional Details

📍 Location: Remote, candidates must be based in Madrid or Barcelona

📄 Contract type: 6-month B2B contract, with possibility to extend

🧑 💻 Experience level: Senior Software Engineer

🌍 Language: Professional English proficiency required

We’re looking for engineers who bring a strong backend mindset, solid testing practices, and a proactive attitude toward continuous improvement .

Interested?

If you’re excited about building scalable systems, solving challenging engineering problems, and working with modern technologies, we’d love to hear from you.

Apply via LinkedIn or reach out directly to discuss the opportunity.