Principal Systems Engineer (C++) - AI Infrastructure

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: AlignerrType: Hourly ContractLocation: RemoteCommitment: 20–40 hours/week What You'll Do Design, build, and optimize high-performance C++ systems that power AI data pipelines and evaluation workflowsDevelop full-stack tooling and backend services for large-scale data annotation, validation, and quality controlHarden reliability, performance, and memory safety across production C++ codebasesCollaborate with data, research, and engineering teams to support model training and evaluation at scaleIdentify bottlenecks and edge cases across data and system behavior, then implement robust, scalable fixesParticipate 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 skillsExperienced full-stack developer with a strong systems programming background5+ years of professional experience writing production-grade C++ for large-scale systemsDeep knowledge of build system architecture and package management strategiesProven 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 frameworksFamiliarity with AI/ML workflows, model training infrastructure, or benchmarking systemsExperience with distributed systems or developer tooling at scale Why Join Us Work directly with leading AI labs on production systems that matterFully remote and flexible — work when and where it suits youFreelance autonomy with the structure of meaningful, high-impact engineering workCollaborate with world-class data, research, and engineering teams pushing the frontier of AIPotential for ongoing work and contract extension as new projects launch