Senior Fullstack Engineer — 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 a unified portfolio of training work, and grow durable freelance careers contributing the human expertise that teaches AI systems.

• Work that directly shapes how modern AI behaves — from annotation to model evaluation.
• Flexible, remote-first opportunities you can fit around life, studies, or other work.

About AI training work

AI training (data labeling/annotation) is the human side of building intelligent systems: people prepare, review, and refine the examples that modern models learn from. Contributors come from many backgrounds — technical and non-technical — and perform work like annotating code, evaluating model outputs, or integrating real-world workflows.

• This role focuses on building software and integrations that produce high-quality inputs for next-generation AI.
• No prior AI research experience is required — domain expertise and solid engineering skills matter most.

The role

OpenTrain is recruiting for a Senior Fullstack Engineer (contract, part-time) to architect and build robust, scalable applications that feed high-quality training data into AI product workflows. The role is remote and open worldwide; expected time commitment is 20+ hours per week.

• Employment type: Contractor, Part-time.
• Time requirement: 20+ hours/week, remote (worldwide).
• Languages: English required.

What you'll do

• Architect and develop production-quality applications using React and modern fullstack frameworks.
• Improve frontend performance through advanced state management and best practices.
• Design and implement backend APIs with secure authentication and data integrity.
• Evaluate architectural tradeoffs to ensure scalability and maintainability.
• Integrate and optimize database solutions to support complex business logic and high traffic.
• Support CI/CD pipelines, deployment processes, and basic DevOps tasks.
• Integrate or automate Adobe InDesign workflows as part of product pipelines.

Requirements

Candidates must demonstrate strong practical experience in fullstack engineering and be comfortable owning architecture and performance work.

• Advanced frontend development with React.
• Backend system design and API development experience.
• Strong understanding of authentication mechanisms and security best practices.
• Database architecture and optimization skills.
• Proven experience improving performance of large-scale systems.
• Familiarity with CI/CD, monitoring, deployment automation, and basic DevOps.
• Experience integrating or automating Adobe InDesign workflows.
• Availability for 20+ hours per week in a contractor, part-time arrangement.
• Experience level: Entry level (posting field); role expects strong practical experience with senior-level responsibilities.

Helpful background

• Experience working on distributed or fully remote engineering teams.
• Prior work on highly scalable or heavily optimized systems.
• Familiarity with modern security and authentication practices.

Compensation, hiring details, and next steps

Compensation is hourly. The listing shows an hourly rate up to $80; the posted range is $30–$80/hr with $80/hr specified as the rate. This is a contractor position; payment is PAY_PER_HOUR.

To apply, prepare examples of relevant fullstack work (React projects, API design, DB schemas, CI/CD examples) and be ready to describe any Adobe InDesign integrations you’ve implemented or automated.

• Pay type: Hourly (PAY_PER_HOUR). Hourly rate: up to $80/hr; range listed $30–$80/hr.
• Work location: Remote, worldwide.
• Employment: Contractor, Part-time.