Backend Developer - Data Annotation Systems

About the Role

What 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 design and build the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve next-generation models.

What You'll Do

• Design, build, and optimize high-performance Python systems that power AI data pipelines and model evaluation workflows
• Develop full-stack backend services and tooling for large-scale data annotation, validation, and quality control
• Build and maintain asynchronous task queues to handle complex, long-running background jobs at scale
• Optimize database queries for high-read/write workloads and serve data via real-time protocols such as WebSockets
• Improve reliability, performance, and safety across existing Python codebases
• Collaborate closely with data, research, and engineering teams to support model training and evaluation workflows
• Identify bottlenecks and edge cases in system and data behavior, then implement scalable, production-ready fixes
• Participate in synchronous design reviews to iterate on architecture and implementation decisions

Who You Are

• Native or fluent English speaker with clear written and verbal communication skills
• Full-stack developer with a strong systems programming background and 3–5+ years of professional Python experience
• Proven experience building and shipping production-grade Python applications
• Experienced with asynchronous task queues and background job processing
• Skilled at optimizing database performance for demanding, high-throughput applications
• Comfortable working with real-time data protocols (e.g., WebSockets)
• Self-directed and reliable — able to commit 20–40 hours per week and deliver consistently without hand-holding

Nice to Have

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

Why Join Us

• Work directly with leading AI labs on production systems that matter
• Fully remote and flexible — structure your work around your schedule
• Freelance autonomy with the substance of high-impact engineering work
• Get hands-on exposure to the cutting edge of AI infrastructure and research workflows
• Potential for ongoing work and contract extension as projects scale