Backend Developer - Data Annotation Systems

Backend Developer — Data Annotation Systems (AI Training)

What if your Python expertise could directly shape the infrastructure that trains 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 every day.

This is a fully remote, flexible contract role for a seasoned engineer who wants to work on real production systems — not toy projects — alongside top-tier research and engineering teams.

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

• Design, build, and optimize high-performance Python systems supporting large-scale AI data pipelines and model evaluation workflows
• Develop full-stack tooling and backend 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 including Web Sockets
• Improve reliability, performance, and safety across existing production Python codebases
• Collaborate with data scientists, researchers, and engineers to support model training and evaluation workflows
• Identify bottlenecks and edge cases across data systems and implement scalable, production-grade fixes
• Participate in synchronous design and code reviews to drive sound architectural decisions

• 3–5+ years of professional experience writing production-grade Python
• Strong full-stack developer with a solid systems programming background
• Experienced building asynchronous task queues and background job systems
• Proficient in optimizing database queries for high-throughput applications
• Comfortable serving and consuming real-time data via Web Sockets or similar protocols
• Clear, precise written and verbal communicator — you can articulate technical decisions well
• Native or fluent English speaker
• Able to commit 20–40 hours per week consistently

• Prior experience with data annotation platforms, data quality systems, or model evaluation infrastructure
• Familiarity with AI/ML workflows, model training pipelines, or benchmarking systems
• Experience designing or maintaining distributed systems
• Background in developer tooling or internal platform engineering

• Work on cutting-edge AI infrastructure alongside leading research labs — this is real, high-stakes work
• Fully remote and async-friendly — work from wherever you do your best thinking
• Freelance autonomy with the structure and consistency of meaningful, ongoing project work
• Make a direct, tangible impact on how next-generation AI models are built, trained, and evaluated
• Potential for ongoing work and contract extension as new projects and partnerships launch