Backend Developer (Spain)

Anyone AI Inc.; España; Remote; EUR 55,000 - 110,000; Part time

Job summary

Anyone AI Inc. is seeking a remote, part-time, project-based expert evaluator to design and assess realistic software engineering tasks, spanning bug fixing, feature development, refactoring, and test generation.

Contributors will work remotely, control their own schedule, provide their own tools, and may serve multiple vendors, with per-project compensation and hourly rate estimates included.

Qualifications

• Advanced English written proficiency required.
• 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 (e.g., pytest, Jest, JUnit, xUnit, Go testing).
• Proven ability to debug and navigate large, multi-file codebases.
• Experience with code reviews, refactoring, and production migrations.

Responsibilities

• 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

Skills

English proficiency

3–7 years exp

Python

JavaScript/TypeScript

Java/C#/Go

Backend/Full-stack

Testing frameworks

Debug multi-file codebases

Code reviews & refactoring

Job description

Qualifications:

• 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 (e.g., pytest, Jest, JUnit, xUnit, Go testing)

• Proven ability to debug and navigate large, multi‑file codebases

• Experience with code reviews, refactoring, and production migrations

Engagement:

Part-time, project-based expert evaluation work

Work Type:

Remote

Contributors will design and evaluate realistic software engineering tasks, including bug resolution, feature implementation, refactoring/migration, and test generation. Work includes both creating complex coding scenarios and reviewing peer submissions for quality and accuracy.

This is a 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).

Responsibilities:

Contributors will:

• 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

Expected Outcomes:

• High-quality, production-realistic coding tasks

• Complete and correct reference implementations

• Robust test coverage and validation artifacts

• Structured, actionable peer review feedback