Senior Backend Engineer (C#) - AI Data Platform

**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