Join OpenTrain as a remote, contract Rust backend developer to build and harden REST/GraphQL APIs and run focused evaluations of AI-powered coding tools (Cursor). Part-time role (<20 hrs/week) paying $30–$90/hr for clear, well-documented backend feedback.
Coding & Software
100% Remote Hourly · $30–$90/hr
$30–$90/hr
Compensation
Worldwide
Eligibility
Entry
Experience
Jun 29, 2026
Posted
Open worldwide
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OpenTrain is the centralized platform where people start and grow careers teaching AI through data labeling and evaluation work. We connect skilled contractors with short-term, focused projects that directly shape how modern AI systems behave.
Work through OpenTrain to build a unified AI training portfolio, apply quickly, and take part in flexible, remote projects that fit around other commitments.
100% remote, flexible project work that fits around your schedule
Work that helps train and evaluate real-world AI systems
Great for freelancers and part-time contributors building a durable AI-focused portfolio
About AI Training Work
AI training (also called data labeling or human feedback work) is the human side of building AI: people provide examples, tests, and evaluations that models learn from. This role focuses on evaluating AI-assisted developer tooling and ensuring backend APIs are robust and secure.
Projects range from annotating and rating model outputs to hands-on testing of tools with clear, structured feedback that engineers can act on.
The Role
You will work as a contract Rust backend developer focused on API development, database work, and hands-on evaluation of AI-powered coding tools. The role combines engineering work (designing and improving REST and GraphQL endpoints, migrations, optimizations) with short, focused testing bursts of AI tools and precise documentation of findings.
This is a part-time contractor role for contributors who can commit to less than 20 hours per week and deliver clear, reproducible feedback in written incident reports and post-burst surveys.
Design, implement, and improve REST and GraphQL endpoints
Test AI coding models and developer tools in Cursor and document issues
Execute database migrations, performance tuning, and schema changes
Communicate findings through structured reports, bug traces, and screenshots
What You’ll Do
Your day-to-day combines backend development tasks with focused evaluation sessions of AI-assisted coding tools. Work will be delivered in short bursts with clear deliverables and documented findings.
Build and optimize REST and GraphQL backend APIs with solid validation and error handling
Improve API security practices and strengthen input validation
Plan and execute database migrations, tuning, and schema evolution
Run hands-on tests of AI-powered coding tools (Cursor) and capture actionable feedback
Submit detailed post-burst surveys, incident reports, and reproduction steps
Requirements
We require demonstrable backend engineering skills with a strong focus on Rust and API development. Clear written communication and the ability to document technical issues precisely are essential.
Strong Rust backend development experience
Experience implementing RESTful and GraphQL APIs
Knowledge of database migrations, performance tuning, and schema design
Extensive use of AI coding tools; familiarity with Cursor is preferred
Clear written and verbal communication skills for remote collaboration
Ability to work as a contractor in a collaborative remote environment
Helpful Background
These qualifications are helpful but not strictly required. They indicate the type of experience that helps you excel in this work and advance to more technical evaluation tasks.
Open source contributions to backend projects
Experience evaluating experimental tooling or developer workflows
A strong interest in AI-assisted software development and tooling
Schedule, Compensation, and Project Details
This is a part-time contractor opportunity: less than 20 hours per week, paid hourly. Work is organized into focused testing bursts and engineering tasks with concrete deliverables.
Pay is hourly in USD. The position lists a pay range of $30–$90 per hour (top pay available up to $90/hr depending on the task and experience).
Employment type: Contractor, Part-time
Time requirement: Less than 20 hours/week
Pay: Hourly, USD, $30–$90/hr (varies by task and experience)
How It Works / How To Apply
OpenTrain is the hiring and contracting organization for this role. Create or use your OpenTrain profile to apply, highlight relevant Rust and API work, and describe your experience using AI coding tools (noting Cursor familiarity if applicable).
Successful applicants will be asked to complete focused testing bursts and deliver clear written reports and survey responses for each assignment.
Prepare examples of Rust backend work and any sample migrations or schema changes
Mention specific experience using AI coding tools and Cursor in your application
Applications are reviewed for technical fit and ability to deliver clear, reproducible feedback
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