Back End Developer (AI Infrastructure)

Alignerr Corp.; Barcelona; Remote; EUR 14,000 - 55,000; Part time

Benefits offered by this job

Fully remote

Flexible hours

Hourly contract

Job summary

Alignerr Corp. in Barcelona is seeking Back End Developers to design, build, and optimize server-side systems and APIs powering AI products.

This is a fully remote, hourly contract role with flexible hours (10–40 hours per week) and scope to contribute to data pipelines, model serving, and scalable microservices. You will work with Python/Go/Java/Node.js/Rust, RESTful APIs, databases, and cloud services, collaborating asynchronously with distributed teams across time zones.

Qualifications

• Proficient in one or more back end languages (Python, Go, Java, Node.js, Rust).
• Strong knowledge of RESTful APIs, microservices, and distributed systems.
• Experience with relational and NoSQL databases (PostgreSQL, MongoDB, Redis).
• Familiar with cloud platforms (AWS, GCP, Azure).
• Experience with Git, CI/CD, and containerization (Docker, Kubernetes).

Responsibilities

• Design, develop, and maintain back end services, APIs, and data pipelines.
• Build scalable server-side architecture for AI training and inference workloads.
• Write clean, well-documented, testable code.
• Integrate with databases, queues, cloud services, and third-party APIs.
• Troubleshoot production issues and conduct code reviews.
• Collaborate asynchronously with distributed teams.

Skills

Python

Go

Java

Node.js

Rust

RESTful API design

Microservices

Distributed systems

Cloud platforms

Git

CI/CD

Docker

Kubernetes

Tools

Docker

Kubernetes

Git

CI/CD pipelines

AWS

GCP

Azure

Job description

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, flexible 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
• Self-motivated, reliable, and effective when working asynchronously without close supervision
• Clear communicator who can document decisions and collaborate across time zones

Nice to Have

• Experience building infrastructure for machine learning or AI systems
• Familiarity with data processing frameworks (Apache Kafka, Spark, Airflow, or similar)
• Background in performance optimization, caching strategies, or high-throughput systems
• Knowledge of authentication, authorization, and security best practices
• Experience with serverless architectures or event-driven design patterns
• Contributions to open-source projects or a strong portfolio of personal/professional work

Why Join Us

• Work on cutting-edge AI infrastructure projects alongside leading research labs
• Fully remote and flexible — set your own hours and work from anywhere
• Freelance autonomy with access to meaningful, technically challenging work
• Build systems at the intersection of software engineering and artificial intelligence
• Collaborate with a global network of talented engineers and researchers
• Potential for ongoing work and contract extension as new projects launch