Senior Python Full-Stack Engineer AI Data & Infrastructure

Senior Python Full-Stack Engineer — AI Data & Infrastructure$50-75/hr Remote Freelance CODINGWhat if your Python expertise could directly shape the infrastructure behind the most advanced AI systems in the world? We're looking for a Senior Python Full-Stack Engineer to build the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve next-generation models.This is a fully remote, flexible contract role working on real production systems — not toy projects. If you're a seasoned Python engineer who thrives on high-impact, technically challenging work, this is where your skills belong.Design, build, and optimize high-performance Python systems supporting large-scale AI data pipelines and evaluation workflowsDevelop full-stack tooling and backend services for data annotation, validation, and quality control at scaleIdentify and eliminate bottlenecks, edge cases, and reliability issues across production codebasesCollaborate closely with data, research, and engineering teams to support model training and evaluation infrastructureImprove safety, performance, and maintainability of existing systemsParticipate in synchronous design reviews and iterate on system architecture with expert colleaguesNative or fluent English speaker with strong written and verbal communication skillsFull-stack developer with a solid systems programming background5+ years of professional experience writing production-grade PythonDeep understanding of performance optimization and concurrency — asyncio, multiprocessing, threading — and type safety tools like Pydantic and mypyProven experience building robust backend services (FastAPI, Django, or similar) or scalable data pipelinesAble to commit 20–40 hours per week with reliability and professionalismPrior experience with data annotation platforms, data quality workflows, or evaluation systemsFamiliarity with AI/ML workflows, model training pipelines, or benchmarking infrastructureExperience with distributed systems, developer tooling, or MLOpsWork directly with leading AI research labs on systems that matterFully remote and flexible — structure your hours around your lifeFreelance autonomy with the depth and consistency of meaningful, long-term technical workCollaborate with a sharp, technically rigorous team on genuinely hard engineering problemsPotential for ongoing work and contract extension as projects scale