About The Role

What if the code you write could directly power the AI systems shaping how millions of people interact with technology? We're looking for Back End Developers in Barcelona to design, build, and optimize the server-side systems and APIs that drive cutting-edge AI products — from data pipelines and model-serving infrastructure to scalable microservices that handle real-world traffic at scale.

This is a fully remote, adaptable contract role. Whether you're a seasoned engineer looking for meaningful project work or a strong developer ready to apply your skills to AI-adjacent infrastructure, this is your chance to build things that matter.

Organization: Alignerr
Type: Hourly Contract
Location: Remote
Commitment: 10–40 hours/week

What You'll Do

Design, develop, and maintain robust back end services, APIs, and data pipelines
Build scalable, high-performance server-side architecture to support AI training and inference workloads
Write clean, well-documented, and testable code following engineering best practices
Integrate with databases, message queues, cloud services,



and third-party APIs
Optimize system performance, reliability, and scalability as usage grows
Collaborate asynchronously with distributed teams of engineers, researchers, and product leads
Troubleshoot production issues, conduct code reviews, and contribute to architectural decisions
Work independently on task-based and project-based assignments on your own schedule

Who You Are

Proficient in one or more back end languages — Python, Go, Java, Node.js, Rust, or similar
Solid understanding of RESTful API design, microservices architecture, and distributed systems
Experienced with relational and/or NoSQL databases (PostgreSQL, MongoDB, Redis, etc.)
Comfortable working with cloud platforms such as AWS, GCP, or Azure
Familiar with version control (Git), CI/CD pipelines, and containerization (Docker, Kubernetes)
Strong problem-solving skills and the ability to debug complex systems independently

📌 Back End Developer (Barcelona)
🏢 Alignerr
📍 Barcelona