Lead Backend Engineer - AI Tooling

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