Senior Backend Engineer (C#) - AI Data Platform

Alignerr Corp.; United States; Remote; GBP 83,000 - 124,000; Part time

Job summary

Alignerr is seeking a Senior Backend Engineer (C#) to design and build high-performance data pipelines, annotation tooling, and evaluation systems powering AI labs. You will shape how data moves, validated results flow between services, and how models are trained at scale.

This fully remote contract role offers 20–40 hours per week and meaningful ownership. You’ll collaborate with data, research, and engineering teams on production-grade systems, RESTful APIs, and RPC services in modern

Qualifications

• 5+ years of professional experience building scalable backend services in C#.
• Strong systems programming background with full-stack exposure.
• Mastery of modern frameworks for building RESTful APIs and RPC services.

Responsibilities

• Design, build, and optimize high-performance backend systems in C#.
• Develop backend services for large-scale data annotation, validation, and quality control.
• Build and maintain RESTful APIs and RPC services for inter-service communication.
• Integrate with cloud-native data services and orchestrate workflows via message bus architectures.
• Improve reliability, performance, and safety across existing C# codebases.
• Identify bottlenecks and edge cases in data and system behavior and implement scalable fixes.
• Collaborate with data, research, and engineering teams to support model training and evaluation workflows.
• Participate in design reviews to iterate on architecture and implementation decisions.

Skills

C#

Backend development

RESTful APIs

RPC services

Cloud-native

Performance tuning

English communication

Tools

REST APIs

Job description

Senior Backend Engineer (C#) — AI Data Platform

About The Role

What if your C# expertise could directly shape the infrastructure powering the next generation of AI? We're looking for a Senior Backend Engineer to design and build the high-performance data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and improve their models.

This is a fully remote contract role with meaningful technical scope. You'll work on real production systems — not toy projects — alongside data, research, and engineering teams at the frontier of AI development.

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

What You'll Do

• Design, build, and optimize high-performance backend systems in C# supporting AI data pipelines and evaluation workflows
• Develop backend services and tooling for large-scale data annotation, validation, and quality control
• Build and maintain RESTful APIs and RPC services for reliable inter-service communication
• Integrate with cloud-native data services and orchestrate workflows via message bus architectures
• Improve reliability, performance, and safety across existing C# codebases
• Identify bottlenecks and edge cases in data and system behavior, then implement scalable, durable fixes
• Collaborate with data, research, and engineering teams to support model training and evaluation workflows
• Participate in synchronous design reviews to iterate on architecture and implementation decisions

Who You Are

• 5+ years of professional experience building scalable backend services in C#
• Strong systems programming background with full-stack exposure
• Mastery of modern frameworks for building RESTful APIs and RPC services
• Experienced with cloud-native data services and message bus / event-driven architectures
• Native or fluent English speaker with clear written and verbal communication skills
• Self-directed and reliable — able to commit 20–40 hours per week and deliver consistently
• Sharp eye for performance bottlenecks, edge cases, and system-level failure modes

Nice to Have

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

Why Join Us

• Work on cutting-edge AI infrastructure projects alongside leading research labs
• Fully remote and flexible — work from anywhere, on a schedule that suits you
• Freelance autonomy with the structure and purpose of high-impact engineering work
• Make a direct, tangible contribution to the systems that shape how AI models are built and evaluated
• Potential for ongoing work and contract extension as new projects launch