Backend Engineering AI Trainer — Contract, Remote

About OpenTrain

OpenTrain is the #1 platform for finding and building careers in AI training and data labeling. We help people discover projects, build unified AI training portfolios, and grow freelance careers working on the human side of AI.

OpenTrain contributors do the real-world work that teaches AI systems how to behave. This listing connects experienced backend engineers with contract work that directly supports model training and real-world data quality.

About AI training work for engineers

AI training (also called data labeling or human feedback work) uses human expertise to create and validate the examples modern AI models learn from. For software engineers, that can mean building, maintaining, and curating backend systems that generate, collect, or validate the technical inputs AI models consume.

This role focuses on backend engineering contributions that improve the quality, reliability, and security of the services and data pipelines used during AI development and evaluation.

The role

OpenTrain is recruiting for a contractor backend engineering role supporting AI system training with real-world technical expertise. You will design, build, and operate backend services, APIs, microservices, and databases used to produce high-quality inputs for AI training.

This is a part-time contractor position (20+ hours per week), open worldwide and conducted remotely. The role emphasizes Python and Java skills, FastAPI and other backend frameworks, cloud deployment, container orchestration, and secure software practices.

What you'll do

• Design, develop, and maintain robust backend services and APIs.
• Architect scalable microservice systems for performance and reliability in cloud environments.
• Model, implement, and optimize relational and NoSQL databases.
• Collaborate with front-end teams to integrate seamless APIs and deliver end-to-end solutions.
• Deploy and manage applications using Docker and Kubernetes.
• Apply best practices in code quality, version control, security, and CI/CD.
• Contribute technical judgment that helps train next-generation AI systems through high-quality real-world input.

Requirements

You must have strong backend engineering experience as described below. No prior AI-specific experience is required, but clear remote communication and discipline are essential.

• Advanced proficiency in Python and Java.
• Hands-on experience with FastAPI and frameworks such as Spring, Django, or Flask.
• Deep understanding of SQL and NoSQL databases, including data modeling, optimization, and query design.
• Strong background in API development, integration, and microservices architectures.
• Experience with Git, containerization (Docker), and orchestration tools like Kubernetes.
• Excellent written and verbal communication skills for remote teamwork.
• Commitment to secure software development and mitigation of vulnerabilities.

Helpful background

The following are not required but will make you a stronger candidate and help you move faster in this role.

• Experience leading backend or cross-functional teams in remote or distributed settings.
• Familiarity with advanced cloud solutions on AWS, Azure, or Google Cloud.
• Experience designing and deploying highly available, mission-critical backend systems.

Compensation, schedule, and how to apply

Pay: $20–$50 per hour (PAY_PER_HOUR). This is a contractor, part-time engagement targeting 20+ hours per week. The project accepts applicants worldwide and work is conducted in English.

To apply, prepare a brief portfolio or summary of relevant backend systems you’ve built (projects, architectures, or repos) and describe your experience with Python/Java, FastAPI/Spring/Django/Flask, databases, and container orchestration. OpenTrain will connect you with the hiring team at OpenTrain for next steps.