Senior Backend Engineer (C#) - AI Data Platform

Alignerr connects top technical experts with leading AI labs to build, evaluate, and improve next-generation models. The Senior Backend Engineer will design and optimize high-performance systems in C# to support AI data pipelines and collaborate with various teams to enhance model training and evaluation workflows.

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

Requirements:

• 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
• 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