Lead Backend Engineer — AI Tooling About The Role What if your Python expertise could directly shape the infrastructure that powers the world's most advanced AI systems? We're looking for a senior backend engineer to build and lead the data pipelines, annotation tooling, and evaluation infrastructure that leading AI labs depend on to train and improve their models. This is a fully remote contract role working on real production systems at the cutting edge of AI development. If you're a senior engineer who wants meaningful, high-impact work — not another CRUD app — this is it. Organization: Alignerr Type: Hourly Contract Location: Remote Commitment: 20–40 hours/week

What You'll Do

Design, build, and optimize high-performance Python systems supporting AI data pipelines and model evaluation workflows Develop backend services and full-stack tooling for large-scale data annotation, validation, and quality control Architect robust APIs (REST/GraphQL), design database schemas, and implement authentication and authorization flows Improve reliability, performance, and safety across existing Python codebases Identify bottlenecks and edge cases in data and system behavior, then implement scalable, production-ready fixes Collaborate with data, research, and engineering teams across model training and evaluation workflows Lead synchronous design and code reviews — driving decisions that shape the architecture of critical AI systems Who You Are Native or fluent English speaker with strong written and verbal communication skills Full-stack developer with a deep systems programming background and 5+ years writing production Python backend services Fluent in modern Python web frameworks with strict type enforcement patterns Experienced architecting scalable APIs, data schemas, and auth systems in production environments A natural leader in code reviews and system design sessions — you can articulate decisions clearly and bring others along Able to commit 20–40 hours per week on a reliable, ongoing basis

Nice to Have

Prior experience with data annotation, data quality pipelines, or AI evaluation systems Familiarity with AI/ML workflows, model training, or benchmarking infrastructure Experience with distributed systems, developer tooling, or platform engineering

Why Join Us

Work directly with leading AI labs on systems that influence next-generation model development Fully remote and flexible — work from wherever you do your best work Freelance autonomy with the structure and stability of ongoing, project-based engagement Make a real, measurable impact on the infrastructure behind some of the most advanced AI in the world Potential for extended engagement and expanded scope as projects grow