Senior Python Full-Stack Engineer — AI Data & Infrastructure

About The Role What if your Python expertise could directly shape the infrastructure behind the world's most advanced AI systems? We're looking for a Senior Python Full-Stack Engineer to build and optimize 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 contract role with meaningful, high-impact work — not filler tasks. You'll be working on real production systems alongside data, research, and engineering teams at the frontier of AI development. Organization: AlignerrType: Hourly ContractLocation: RemoteCommitment: 20–40 hours/week What You'll Do Design, build, and optimize high-performance Python systems supporting AI data pipelines and model evaluation workflowsDevelop full-stack tooling and backend services for large-scale data annotation, validation, and quality controlImprove reliability, performance, and safety across existing Python codebasesCollaborate with data, research, and engineering teams to support model training and evaluation workflowsIdentify bottlenecks and edge cases in data and system behavior, and implement scalable fixesParticipate in synchronous design reviews to iterate on system architecture and implementation decisions Who You Are Native or fluent English speaker with clear written and verbal communication skillsExperienced full-stack developer with a strong systems programming background5+ years of professional experience writing production-grade PythonDeep understanding of performance optimization and concurrency — asyncio, multiprocessing, threadingComfortable with type safety tooling such as Pydantic and mypyProven track record building robust backend services (FastAPI, Django) or scalable data pipelinesAble to commit 20–40 hours per week consistently Nice to Have Prior experience with data annotation, data quality systems, or model evaluation infrastructureFamiliarity with AI/ML workflows, model training pipelines, or benchmarking systemsExperience with distributed systems or developer tooling Why Join Us Work on cutting-edge AI infrastructure alongside leading research labsFully remote and flexible — work when and where it suits youFreelance autonomy with the depth and impact of a senior engineering roleContribute directly to systems that shape how next-generation AI models are built and evaluatedPotential for ongoing work and contract extension as new projects launch