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Anyone AI
Anyone AI

Full-Stack Developer - AI Trainer

RemoteSpain only
Published
Role
Fullstack
Experience
Senior
Employment
Contract
$45–$80/hr
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Open to ES only. Set where you work from to check your eligibility.

No BS summary

Part-time contract full-stack developer in Spain for AI training/evaluation work. Needs 3–7 years of software engineering experience, strong Python and JavaScript/TypeScript, testing frameworks, code review/refactoring experience, and advanced written English.

Core skills

PythonJavaScript/TypeScript

Required skills

Java/C#/GopytestJestJUnitxUnitGo testing

Required languages

English Advanced professional written proficiency | required | true | plus | false | optional | false | required=true | optional=false | nice_to_have=false | mandatory=true | is_required=true | plus=false | preference=false | advantage=false | required: true | required_flag: true | status: required | qualifier: required | proficiency: Advanced professional written proficiency | requirement_type: required | must_have: true | nice_to_have: false | optional: false | explicit_requirement: true | note: schema has no separate required boolean, so requirement is encoded here.

What you'll do

  • Design and evaluate realistic software engineering tasks, including bug resolution, feature implementation, refactoring/migration, and test generation.
  • Create complex coding scenarios.
  • Review peer submissions for quality and accuracy.
  • Design and implement multi-file coding tasks across bug fixing, feature development, refactoring, and testing.
  • Write clear natural-language specifications and reference implementations.
  • Develop and extend unit and integration test suites.
  • Review peer-generated tasks for correctness, clarity, and realism.
  • Identify edge cases, ambiguities, and potential failure modes.
  • Ensure alignment between specifications, code, and expected outputs.

What they require

  • Advanced professional written proficiency in English.
  • 3–7 years of professional software engineering experience.
  • Strong proficiency in Python and JavaScript/TypeScript; working knowledge of Java, C#, or Go.
  • Backend or full-stack development experience in production systems.
  • Experience with testing frameworks such as pytest, Jest, JUnit, xUnit, or Go testing.
  • Proven ability to debug and navigate large, multi-file codebases.
  • Experience with code reviews, refactoring, and production migrations.
  • Part-time, project-based expert evaluation work.
  • Project-based consultant role.
  • Consultants will be paid on a per-project basis; hourly rates are estimates based on anticipated completion time.
  • Consultants control their own schedule, provide their own tools, and may simultaneously provide services to other vendors/employers, subject to those vendors’ allowances.

Benefits

  • Consultants control their own schedule.
  • Consultants may simultaneously provide services to other vendors/employers, subject to those vendors’ allowances.

We create high-quality STEM training data for frontier AI models. Our data is used directly in training and evaluation pipelines at leading AI labs to improve model reasoning in technical domains.

AIStartupanyoneai.com/
$45–$80/hr