Our client is looking for a Mid BackEnd Engineer with a strong focus on API development to join their Product Development team. You will contribute to designing and building scalable backend services that power high-impact, data-driven products in the renewable-energy technology space.

If you enjoy solving complex problems, writing clean and reliable code, and working with modern cloud-native architectures, this role will place you right at the core of a mission-driven engineering environment.

📍 Central Barcelona (very well connected).

💻 SaaS platform

Key Responsibilities

• Develop, maintain, and document RESTful APIs for both public and internal use.
• Write clean, maintainable, and testable code following best engineering practices.
• Troubleshoot, debug, and optimise existing APIs and backend services.
• Diagnose and solve complex problems across API layers, database queries and cloud environments.
• Participate in code reviews and contribute to architectural and performance improvements.
• Collaborate with cross-functional teams to design and deliver scalable interfaces.
• Stay up to date with the team’s technologies and share knowledge proactively.

Requirements

Mandatory

• 3–5 years of experience in backend development, with strong focus on APIs.
• Solid knowledge of TypeScript and Node.js (experience in other languages is welcome, but TypeScript understanding is essential).
• Experience working with cloud environments (AWS preferred, but other cloud providers are also acceptable).
• Experience with relational databases (PostgreSQL is a strong plus).
• Strong understanding of REST API design and principles.
• Experience using Git, pull requests and CI/CD workflows.
• Knowledge of clean code principles, design patterns, software architecture, cloud fundamentals and API-first development.
• Strong communication skills in English, both written and verbal.

Nice to Have

• Experience with Serverless, especially AWS Lambda and API Gateway.
• Experience with event-driven systems (Kafka, AWS SQS, RabbitMQ…).
• Knowledge of Terraform or Infrastructure as Code.
• Familiarity with observability practices and tools: Grafana, CloudWatch, Express logging, etc.
• Awareness of database modelling best practices.
• Interest in mentoring or sharing knowledge within the team.

What Our Client Offers

• The opportunity to work on impactful products that accelerate the adoption of clean and reliable energy.
• A collaborative, mission-driven and diverse engineering environment.
• Continuous learning in cloud, serverless, APIs, and scalable architecture.
• Hybrid work modality (2 days of home office)
• Salary range 40K–50K (depending on experience)