Senior Software Engineer (Remote | $30–$100/hr)

Synthires; Greater London; On-site; GBP 31,000 - 103,000; Full time

Job summary

Synthires is seeking experienced Software Engineers to support an AI training project focused on creating realistic, challenging coding tasks and reliable evaluation systems.

No prior AI experience is required—your software engineering expertise is what matters. You will implement deterministic verifiers, debug and optimize code, and contribute to scalable backend systems.

You will create coding tasks, design automated tests, and ensure quality and performance across the project.

Qualifications

• Strong backend experience with multiple languages and frameworks.
• Experience building scalable services and APIs.
• Strong debugging, performance optimization, and automated testing skills.
• Solid code review and software engineering judgment.
• Experience with testing strategies and large test suites is valued.
• Strong understanding of algorithms, data structures and CS fundamentals.

Responsibilities

• Create realistic and challenging coding tasks.
• Implement deterministic verifiers that accept valid solutions and reject incorrect ones.
• Debug, test, optimize, and refactor existing codebases.
• Design and maintain automated tests and testing strategies.
• Identify performance bottlenecks, bugs, and system issues.
• Review code and evaluate technical solutions for quality and correctness.

Skills

Backend development

Java/Go/Python/C++

API design

Debugging

Testing

Job description

We are seeking experienced Software Engineers to support an AI training project focused on creating realistic, challenging coding tasks and reliable evaluation systems. You’ll apply your software engineering expertise to help AI systems improve their ability to solve real-world programming problems.

No prior AI experience is required — your software engineering expertise is what matters.

Key Responsibilities

• Create realistic and challenging coding tasks involving feature implementation and bug fixes.
• Implement deterministic verifiers that accept valid solutions and reject incorrect ones.
• Debug, test, optimize, and refactor existing codebases.
• Design and maintain automated tests and reliable testing strategies.
• Identify performance bottlenecks, bugs, and system issues.
• Review code and evaluate technical solutions for quality and correctness.

Required Qualifications

• Strong backend experience with Java, Node.js, Go, Rust, TypeScript, Python, C++, or similar.
• Experience building scalable services and APIs.
• Strong skills in debugging, performance optimization, and automated testing.
• Solid code review and software engineering judgment.
• Experience with testing strategies, large test suites, flaky tests, or quality improvement is highly valued.
• Strong understanding of algorithms, data structures, and computer science fundamentals.

Preferred Qualifications

• Proven experience delivering high-quality and performant backend systems.
• Experience resolving software bugs and system bottlenecks.
• Experience with codebase refactoring and complex feature implementation.
• Strong analytical, problem-solving, and technical communication skills.

Compensation

• Output-based compensation of $30–$100/hour equivalent, paid per qualifying task.
• Approximately 15 hours/week with a flexible schedule.
• Approximately 300 positions available.
• Minimum weekly submission requirements apply.