Principal Software Engineer – .NET, AWS & AI

** About the Role
**** hands-on Principal Software Engineer with deep, recent C#/.NET Core and AWS experience building large-scale distributed systems and cloud-native platforms**, along with experience applying
** AI/ML, Generative AI, large language models (LLMs), retrieval-augmented generation (RAG), or agentic AI capabilities in production environments.
** This is a
** Principal-level individual contributor role
** requiring demonstrated ownership of
** architecture and technical direction for complex, enterprise-scale production systems**. The successful candidate will have operated at
** Principal Engineer or equivalent scope**, influencing multiple engineering teams while
** remaining actively hands-on with architecture, design, development, and implementation.
** You will play a key role in the modernization and evolution of our U.S. tax compliance solutions, helping establish technical direction, improve platform scalability and reliability, and responsibly incorporate AI-enabled capabilities into our products.

Candidates outside the Washington, DC area must be willing and able to travel to the Washington, DC office as needed.
* ** Own architecture and system design for complex, large-scale production platforms**, making technical decisions around scalability, reliability, performance, security, and maintainability.
* ** Design and build production software using C#/.NET Core and AWS**, remaining actively involved in implementation, technical problem-solving, design reviews, and engineering delivery.
* ** Lead the modernization of complex legacy applications into cloud-native architectures**, including distributed systems, microservices, APIs, data services, and containerized workloads.
* ** Establish technical direction and influence architecture and engineering decisions across multiple teams.
*** Provide hands-on technical leadership through architecture and design reviews, code guidance, troubleshooting, mentoring, and engineering best practices.
* Identify and help implement opportunities to incorporate
** AI/ML and Generative AI capabilities into production products.
*** Contribute to the long-term technical roadmap and communicate architecture decisions, trade-offs, risks, and recommendations.
** About You
** You're a fit for this Principal Software Engineer role if you bring:
* 10+ years of professional software engineering experience with demonstrated
** Principal Engineer or equivalent senior individual contributor scope.**
* ** Strong, recent, hands-on C#/.NET Core engineering experience, including personally designing and implementing production software.**
* ** Deep, hands-on production experience with Amazon Web Services (AWS)**, designing and implementing cloud-native systems using multiple AWS services such as
** EC2, S3, Elastic Load Balancing, Auto Scaling, RDS, Lambda, SQS, and container services.**
* ** Proven experience architecting AND implementing large-scale distributed systems, microservices, APIs, and highly available production applications.**
* ** Demonstrated experience modernizing complex legacy applications into scalable, resilient cloud-native solutions.**
* ** Principal-level architecture and system design ownership**, including making significant technical trade-offs, setting technical direction, and influencing engineering decisions across multiple teams.
* ** Proven ability to remain hands-on with engineering delivery while providing Principal-level technical leadership.
*** Strong knowledge of software architecture, object-oriented design, data structures, algorithms, design patterns, API design, relational databases, and modern engineering practices.
* Strong communication and collaboration skills with the ability to influence across Product, Engineering,…