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 systems? 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 their models.

This is a fully remote, flexible contract role with meaningful technical depth and real production impact. If you thrive on building systems that scale — and want to work on some of the most consequential infrastructure in AI right now — this is the role for you.

• Organization: Alignerr
• Type: Hourly Contract
• Location: Remote
• Commitment: 20–40 hours/week

What You'll Do

• Design, build, and optimize high-performance Python systems that power AI data pipelines and evaluation workflows
• Develop full-stack backend tooling and services for large-scale data annotation, validation, and quality control
• Build and maintain asynchronous task queues to handle long-running background jobs reliably at scale
• Optimize database queries for high-read/write workloads and serve data via real-time protocols including WebSockets
• Identify bottlenecks, edge cases, and failure modes in data and system behavior — then implement robust, scalable fixes
• Improve reliability, performance, and safety across existing Python codebases
• Collaborate directly with data, research, and engineering teams supporting model training and evaluation workflows
• Participate 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 skills
• Experienced full-stack developer with a strong systems programming background
• 3–5+ years of professional experience writing production-grade Python
• Proven track record building asynchronous task queues for background processing at scale
• Comfortable optimizing complex database queries and serving data in real time
• Self-directed and reliable — you can commit 20–40 hours per week and deliver consistently

Nice to Have

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

Why Join Us

• Work directly on production systems used by leading AI research labs
• Fully remote and async-friendly — work from wherever you do your best work
• Freelance autonomy paired with high-impact, technically meaningful projects
• Collaborate with world-class researchers and engineers at the frontier of AI development
• Potential for ongoing work and contract extension as new projects launch