Position: Senior Full-Stack Software Engineer Type: Contractor Compensation: $50–$100 per hour equivalent (paid per accepted task)

Location:
Fully Remote (Worldwide) About the Opportunity We are seeking highly skilled Senior Full-Stack Software Engineers to contribute to an AI training project focused on software development, technical problem-solving, debugging, system architecture, and code evaluation. In this role, you will create, solve, review, and validate challenging software engineering tasks across front-end and back-end systems. You will also work on translating complete coding projects from one programming language to another. This position requires substantial hands-on experience across the full application stack. Candidates should be comfortable developing and debugging both user-facing applications and the backend services that support them, rather than specializing exclusively in one layer.

Key Responsibilities
Develop, modify, and debug front-end and back-end application components. Implement user-facing features alongside the services, APIs, and data models that support them. Navigate unfamiliar code repositories and understand existing application architecture. Diagnose and resolve issues involving application state, API contracts, authentication, data persistence, networking, and deployment. Evaluate, improve, and translate code across multiple programming languages.



Review AI-generated solutions for correctness, completeness, performance, security, and maintainability. Create and validate technically challenging software engineering tasks for AI training and evaluation. Provide clear technical feedback on implementation quality, debugging approaches, and system design. Required Qualifications Meaningful hands-on experience in both front-end and back-end engineering. Experience understanding and contributing to the architecture of complete software systems. Ability to navigate and work effectively in unfamiliar codebases. Strong debugging, analytical, and technical problem-solving skills. Preferred Qualifications Experience working across diverse technology stacks and programming languages. Familiarity with modern front-end frameworks, backend architectures, and API development. Experience with database design, authentication systems, networking, and external service integrations. Ability to assess code quality, performance, security, and maintainability. Experience reviewing AI-generated code or contributing to software engineering evaluation projects. Compensation & Engagement Compensation: $50–$100 per hour equivalent, paid per accepted task. Work Arrangement: Fully remote, worldwide. Time Commitment: Approximately 15 hours per week. Weekly Requirement: A minimum number of tasks must be submitted each week.

📌 Senior Full Stack Engineer (España)
🏢 Synthires
📍 España