Backend Software Engineer — AI Model Evaluation

About OpenTrain

OpenTrain is the #1 platform for finding and building careers in AI training and data labeling. We help people discover projects, build a unified AI training portfolio, and grow a durable freelance career in a fast‑growing industry.

Our platform focuses on transparent rates, reliable payments, and ongoing upskilling so contributors can earn, learn, and shape how AI systems behave.

About AI Training Work

AI training (also called data labeling or human feedback) is the human side of building modern AI: people prepare and review examples that teach models to write, code, reason, and act. This work is largely remote, flexible, and accessible — a great way for engineers to apply domain skills while directly improving model behavior.

This role centers on technical evaluation and code-focused tasks: you will create environments and examples that help train and evaluate next‑generation models.

The Role

OpenTrain is recruiting Software Engineers to support a customer project focused on backend development and AI model evaluation. You will use your programming skills to build reinforcement learning environments, implement backend services, solve programming tasks, and provide high‑quality code review and technical feedback.

This is a remote, part‑time contractor role requiring roughly 10–12 hours per week. The public pay range is $40–$75 per hour.

What You'll Do

You will combine hands‑on engineering with clear documentation and evaluation work to help train models that understand and generate reliable code.

• Build and maintain reinforcement learning environments that exercise real backend programming tasks.
• Write backend services and supporting code using languages such as Java, Python, Node.js, Go, or Rust.
• Create thorough unit and integration tests and aim for high test coverage.
• Review code for correctness, performance, maintainability, and security, and provide clear, actionable feedback.
• Solve programming tasks and document technical reasoning to improve AI model quality.
• Work asynchronously with a distributed team and document engineering decisions clearly.

Requirements

You must demonstrate solid backend engineering experience and the ability to communicate technical decisions in writing.

• Strong experience in backend development with Java, Node.js, Go, Rust, or similar.
• Proven experience building scalable backend systems and APIs.
• Expertise in debugging, performance optimization, and automated testing.
• Strong understanding of software engineering best practices and code review.
• Excellent written and verbal communication skills (English required).
• Experience working effectively in remote, distributed teams.

Helpful Background (Optional)

The following skills are not required but will make your work more valuable to the project.

• Cybersecurity/SecOps experience: application security, secure coding, penetration testing, vulnerability assessment, OWASP/CWE, or security‑focused code reviews.
• Familiarity with AI, data‑driven engineering, or large‑scale technical projects.

Schedule, Pay, and Logistics

This role is fully remote and open globally. Expect to commit about 10–12 hours per week as a contractor. The advertised pay range is $40–$75 per hour.

Work will involve coding tasks, code reviews, and written evaluations; labeling types include evaluation ratings and programming/coding assessment. The project uses a third‑party labeling tool (listed as OTHER).

• Employment type: Contractor, Part‑time.
• Languages: English.
• Time requirement: Less than 20 hours/week (10–12 hrs/week typical).

Who Should Apply & How It Works

Apply if you are a backend engineer who enjoys writing high‑quality code, reviewing others' work, and documenting technical reasoning to improve AI systems. This role suits professionals who want flexible, impactful part‑time work that contributes directly to how models learn to code.

On OpenTrain you’ll create a profile, review project details, and apply. We show rates up front, handle payments reliably, and provide resources to help you succeed.

• To apply: create an OpenTrain account, complete your profile, and submit your application to this project.
• You will be evaluated on technical skill, attention to detail, and ability to write clear, actionable feedback.