Fullstack Engineer — AI Training Platform

About OpenTrain

OpenTrain is the #1 platform for people building careers in AI training and data labeling. We help contributors discover projects across the industry, build a single professional profile that showcases their AI‑training work, and apply in minutes to roles that fit their skills and availability.

About AI training work

AI training (also called data labeling or human feedback work) is the human core of modern AI systems: people create, validate, and evaluate the examples models learn from. That work is highly accessible, often remote and flexible, and contributors directly influence how models behave and perform in the real world.

The role

OpenTrain is recruiting a Fullstack Engineer (contract, part‑time) to design and deliver scalable frontend and backend solutions that support AI training workflows. You will build APIs and interfaces that enable high‑quality data input, evaluation, and annotation for code‑related labeling tasks.

This is a remote, worldwide role at 20+ hours per week. The position is entry level (candidates with a CS degree or equivalent practical experience are welcome). Pay is hourly in USD, range $30–$80/hr (top rate $80/hr). English is required.

• Employment type: Contractor, Part‑time
• Time requirement: 20+ hours/week
• Languages: English
• Pay: USD hourly, $30–$80/hr (up to $80/hr)
• Labeling domain: Computer code / programming and evaluation/rating tasks
• (integrations with third‑party tooling possible)

What you'll do

You will work across the stack to translate product and project needs into reliable technical solutions that support AI training and evaluation.

• Develop, test, and deploy scalable frontend and backend solutions to meet evolving business requirements.
• Design and implement RESTful APIs (or GraphQL where appropriate) to enable seamless communication between system components.
• Collaborate with UX/UI designers to deliver intuitive and engaging user experiences for annotators and reviewers.
• Participate in code reviews and maintain high standards for code quality, maintainability, and documentation.
• Troubleshoot, debug, and optimize application performance across the stack.
• Work closely with project teams to translate labeling and evaluation requirements into technical implementations.

Requirements

Candidates must demonstrate practical fullstack experience and the ability to contribute in a distributed remote team. The list below repeats the role's required skills as provided.

• Proven hands‑on experience with both frontend and backend frameworks.
• Expertise in designing, building, and consuming APIs (RESTful or GraphQL).
• Strong understanding of modern web technologies, architectures, and development methodologies.
• Experience using version control systems such as Git.
• Demonstrated ability to collaborate effectively in a remote, distributed team setting.
• Excellent problem‑solving and analytical skills with a detail‑oriented approach.
• Bachelor's degree in Computer Science or a related technical field, or equivalent practical experience.

Helpful background

The following are not required but will help you move faster on day one and contribute to infrastructure and process improvements.

• Familiarity with DevOps practices and cloud‑based infrastructure.
• Experience with automated testing frameworks and CI/CD pipelines.
• Background working in Agile/Scrum development environments.

How to apply

Apply through OpenTrain to submit your profile, highlight relevant fullstack work, and state your availability. Make sure to include examples or links to projects that show your frontend and backend experience and any API or infrastructure work.

OpenTrain connects contributors with AI training projects and helps you build a portfolio of annotation and evaluation work that grows your career in this fast‑moving field.

• Prepare a brief summary of relevant projects and your weekly availability (20+ hrs/week).
• Include links to code samples, repositories, or a portfolio if available.
• Applications are accepted worldwide; English proficiency is required.