Senior Backend Engineer (C#) — AI Data Platform
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 build and optimize the data pipelines, annotation tooling, and evaluation systems that leading AI labs depend on to train and benchmark frontier models.
This is a fully remote, flexible contract role for an experienced engineer who wants to work on genuinely hard problems at the intersection of software engineering and AI research — without the constraints of a full-time role.
- 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# that power 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 across message bus architectures
- Improve reliability, performance, and safety across existing production C# codebases
- Collaborate with data, research, and engineering teams to support model training and evaluation workflows
- Identify bottlenecks and edge cases in system behavior and implement scalable, maintainable fixes
- Participate in synchronous design reviews to iterate on system architecture and implementation decisions
Who You Are
- 5+ years of professional experience building scalable backend services in C#
- Strong systems programming background with a deep understanding of performance and reliability trade-offs
- Mastery of modern frameworks for building RESTful APIs and RPC services
- Solid experience integrating with cloud-native data services and message bus architectures
- Native or fluent English speaker with clear written and verbal communication skills
- Self-directed and dependable — you can commit 20–40 hours per week and deliver without hand-holding
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 design or developer tooling
- Background in full-stack development alongside strong backend fundamentals
Why Join Us
- Work on real production systems used by leading AI research labs — this is high-impact engineering, not toy projects
- Fully remote and async-friendly — work when and where you do your best thinking
- Freelance autonomy with the structure of meaningful, ongoing technical work
- Collaborate with engineers and researchers at the cutting edge of AI development
- Potential for ongoing contract extension as projects scale and new work launches