Senior Backend Engineer (C#) - AI Data Platform

Labelbox; Remote; GBP 80,000 - 100,000; Part time

Job summary

A tech company specializing in AI data is looking for a Senior C# Full-Stack Engineer to design and optimize systems for AI data pipelines. This contract position is remote, requiring a commitment of 20–40 hours per week. Candidates must have at least 5 years of experience in C# and full-stack development, along with strong communication skills. The hourly compensation is competitive, ranging from $50 to $75 based on experience.

Qualifications

• Native or fluent English speaker.
• 5+ years of experience building scalable backend services in C#.
• Mastery of frameworks for RESTful APIs.

Responsibilities

• Design, build, and optimize high-performance systems in C#.
• Develop full-stack tooling and backend services.
• Collaborate with teams to support model training.

Skills

C# development

Full-stack development

RESTful APIs

Cloud-native services

Communication skills

Job description

About the Job

Alignerr connects top technical experts with leading AI labs to build, evaluate, and improve next-generation models. We work on real production systems and high-impact research workflows across data, tooling, and infrastructure.

Position

Senior C# Full-Stack Engineer — AI Data & Infrastructure

Type: Contract, Remote Commitment: 20–40 hours/week Compensation: Competitive, hourly (based on experience)

Role Responsibilities

• Design, build, and optimize high-performance systems in C# supporting AI data pipelines and evaluation workflows
• Develop full-stack tooling and backend services for large-scale data annotation, validation, and quality control
• Improve reliability, performance, and safety across existing C# codebases
• Collaborate with data, research, and engineering teams to support model training and evaluation workflows
• Identify bottlenecks and edge cases in data and system behavior, and implement scalable fixes
• Participate in synchronous reviews to iterate on system design and implementation decisions

Qualifications

Must-Have

• Native or fluent English speaker
• Full-stack developer experience with a strong systems programming background
• 5+ years of professional experience building scalable backend services in C#.
• Mastery of modern frameworks for building RESTful APIs and RPC services for inter-service communication.
• Experience integrating with cloud-native data services and orchestrating workflows via message bus architectures.
• Clear written and verbal communication skills.
• Ability to commit 20–40 hours per week.

Preferred

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

Application Process

• Submit your resume
• Complete a short technical screening
• Project matching and onboarding

$50 - $75 an hour