Senior Backend Engineer (C#) - AI Data Platform
Role summary
Alignerr is seeking a Senior C# Full-Stack Engineer for a remote, contract role focused on building and optimizing AI data platforms and infrastructure. The engineer will design, develop, and enhance high-performance C# backend services and full-stack tooling for large-scale data annotation, validation, and quality control. Responsibilities include improving system reliability and performance, collaborating with cross-functional teams, and identifying/resolving system bottlenecks. The role requires 5+ years of backend C# experience, mastery of RESTful APIs and RPC services, and experience with cloud-native data services and message bus architectures. Familiarity with AI/ML workflows and data annotation systems is preferred.
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