Principal Systems Engineer (C++) - AI Infrastructure

About the job Principal Systems Engineer (C++) — AI Infrastructure About The Role What if your deep C++ expertise could directly shape the infrastructure powering the world's most advanced AI systems? We're looking for a Principal Systems Engineer to design and build the high-performance data pipelines, annotation tooling, and evaluation infrastructure that leading AI labs depend on to train and improve next-generation models. This is a fully remote, flexible contract role for senior engineers who want to work on real production systems with genuine impact — not toy projects. Organization: Alignerr Type: Hourly Contract Location: Remote Commitment: 20–40 hours/week What You'll Do Design, build, and optimize high-performance C++ systems that power AI data pipelines and evaluation workflows Develop full-stack tooling and backend services for large-scale data annotation, validation, and quality control Harden reliability, performance, and memory safety across production C++ codebases Collaborate with data, research, and engineering teams to support model training and evaluation at scale Identify bottlenecks and edge cases across data and system behavior, then implement robust, scalable fixes Participate in synchronous design reviews to iterate on architecture and implementation decisions Who You Are Native or fluent English speaker with clear written and verbal communication skills Experienced full-stack developer with a strong systems programming background 5+ years of professional experience writing production-grade C++ for large-scale systems Deep knowledge of build system architecture and package management strategies Proven experience designing reliable systems with rigorous error handling and memory safety (sanitizers, ASAN, TSAN, etc.) Able to commit 20–40 hours per week with consistency Nice to Have Prior experience with data annotation, data quality pipelines, or evaluation frameworks Familiarity with AI/ML workflows, model training infrastructure, or benchmarking systems Experience with distributed systems or developer tooling at scale Why Join Us Work directly with leading AI labs on production systems that matter Fully remote and flexible — work when and where it suits you Freelance autonomy with the structure of meaningful, high-impact engineering work Collaborate with world-class data, research, and engineering teams pushing the frontier of AI Potential for ongoing work and contract extension as new projects launch