Principal Software Engineer

Principal Software Engineer – C#/.NET Core & AWS | AI-Enabled Platforms | $200,000 - $240,000 + bonus & RSUs | Hybrid (3-days in office) I’m recruiting for a global leader in professional information and enterprise software, and they need a hands-on Principal Engineer to help modernise a major U.S. tax compliance platform. The opportunity This is a true Principal IC role: you’ll own architecture and technical direction for large-scale production systems, shape decisions across multiple engineering teams, and stay close to the code. No ivory tower. What you’ll do Own architecture and system design for complex, high-scale platforms, balancing scalability, reliability, performance and security Build production software in C#/.NET Core on AWS, staying hands-on in design, delivery and problem-solving Lead the move from legacy applications to cloud-native architectures: microservices, APIs, distributed systems and containerised workloads Set technical direction and influence engineering decisions across teams Mentor through design reviews, code guidance and best practice Identify and deliver practical uses of AI/ML and Generative AI in production products Help shape the long-term technical roadmap and communicate trade-offs and risks What you’ll bring 10+ years in software engineering, with proven Principal-level (or equivalent senior IC) scope Strong, recent, hands-on C#/.NET Core experience Deep production AWS experience across services such as EC2, S3, ELB, Auto Scaling, RDS, Lambda, SQS and container services A track record of architecting and building large-scale distributed systems, microservices and highly available applications Experience modernising complex legacy systems into resilient, cloud-native solutions Strong grounding in architecture, OO design, algorithms, design patterns, API design and relational databases Excellent communication, able to influence across Product, Engineering, Security, QA, Data and Ops Degree in Computer Science or a related field, or equivalent experience