Senior Backend Engineer (C#) - AI Data Platform

Alignerr is seeking a Senior Backend Engineer to design and build high-performance data pipelines for AI applications. The role involves developing backend services, optimizing systems, and collaborating with teams to support AI model training and evaluation workflows.

Responsibilities:

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

Requirements:

• 5+ years of professional experience building scalable backend services in C#
• Deep command of modern C# frameworks for RESTful APIs and RPC-based inter-service communication
• Experienced integrating with cloud-native data services and message bus architectures
• Systems-level thinker who can identify performance issues and architect clean, scalable solutions
• Clear, concise written and verbal communicator — comfortable working with cross-functional teams
• Native or fluent English speaker
• Able to commit 20–40 hours per week consistently
• Prior experience with data annotation platforms, data quality systems, or evaluation pipelines
• Familiarity with AI/ML workflows, model training, or benchmarking infrastructure
• Experience with distributed systems design or developer tooling
• Full-stack background with frontend exposure alongside a strong backend foundation