Backend Developer - Data Annotation Systems

Backend Developer - Data Annotation Systems (AI Infrastructure) About the Role What if your Python expertise could directly shape the infrastructure behind the world's most advanced AI models? 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, flexible contract role for an experienced engineer who wants to work on real production systems with meaningful impact - not toy projects. 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 large-scale AI data pipelines and evaluation workflows Develop full-stack backend tooling and services for data annotation, validation, and quality control at scale Build and maintain asynchronous task queues to handle long-running background jobs reliably Optimize database queries for high-read/write workloads and serve data via real-time protocols such as WebSockets Improve reliability, performance, and robustness across existing Python codebases Identify bottlenecks and edge cases in data and system behavior, and implement scalable, production-ready fixes Collaborate closely with data, research, and engineering teams to support model training and evaluation workflows Participate in synchronous design reviews to iterate on system architecture and implementation decisions Who You Are Strong full-stack developer with a solid systems programming background 3-5+ years of professional experience writing production-grade Python Experienced building asynchronous task queues for long-running background processing Proficient in optimizing database queries for high-throughput applications Comfortable working with real-time data protocols (e.g., WebSockets) Clear, precise written and verbal communicator Able to commit 20-40 hours per week consistently Native or fluent English speaker Nice to Have Prior experience with data annotation platforms, data quality systems, or evaluation pipelines Familiarity with AI/ML workflows, model training, or benchmarking infrastructure Experience with distributed systems or developer tooling Background working alongside research or data science teams Why Join Us Work directly with leading AI labs on production systems that matter Fully remote and flexible - work from anywhere on a schedule that suits you Freelance autonomy with the structure of high-quality, technically challenging work Contribute to AI infrastructure that influences how next-generation models are built and evaluated Potential for ongoing work and contract extension as new projects launch