Principal Software Engineer-AI

#
** Our Privacy Statement & Cookie Policy
** This posting is for proactive recruitment purposes and may be used to fill current openings or future vacancies within our organization.
** Principal Software Engineer-AI
** Thomson Reuters is building the AI platform that will power the next decade of tax and accounting products, including  – a suite of AI‑native products used by accountants on real client work every day. As a
** Principal Software Engineer**, you will own core backend and AI orchestration systems that turn frontier models into reliable, production‑grade workflows s role is for the
** CoCounsel for Tax and Accounting team**, formed from the recent acquisition of the startup .
** Why this role is different:**
* ** Own the AI backbone**:
You will be the principal engineer responsible for the backend and orchestration layer powering AI agents, conversations, work spaces, and knowledge base across CoCounsel for Tax and Accounting.
* ** Shape the company's AI platform and patterns**:
Define patterns for building MCP servers, designing agents, novel uses of LLMs, experimentation, and scalable infrastructure. Your decisions will influence multiple product lines, not just a single feature.
* ** Work at real production scale**:
Build and evolve systems that operate over millions of documents, highly structured tax data, ever changing laws, and thousands of concurrent AI interactions from accountants doing time‑sensitive work.
* ** Small team, big surface area**:
Join a tight group of senior engineers and researchers shipping quickly, with direct access to product leadership and customers. Think ownership of a startup with the runway of a public company.
* ** Great fit for managers who miss building**:
This role is intentionally designed for senior engineers and engineering managers who want to move back into a high‑impact IC track. You keep the scope and influence of an EM – driving multi‑team initiatives, setting technical direction, mentoring senior engineers – but spend most of your time in the code and architecture of AI systems instead of in 1:1s and status meetings.
** About the Role   
* In this role as a
* Principal Software Engineer-AI
* you will:
***** Technical leadership and cross‑functional influence
*** Lead multi‑quarter initiatives that cut across AI, product, and infra (e.g., a new orchestration layer, a low-latency retrieval system, or a unified knowledge base).
* Mentor staff and senior engineers, raising the bar on system design, code quality, and AI integration practices across the org.
* Be the expert in new model capabilities, collaborating closely with AI/ML engineers, researchers, designers, and PMs to translate industry improvements into reliable, user‑facing workflows that accountants trust.
* Help shape the team’s roadmap, technical strategy, and engineering culture – from experimentation practices to testing, rollout, and postmortems.
** Design and own AI‑first backend systems
*** Architect and implement backend services (Python, FastAPI, Postgre

SQL, AWS, Vercel) that power generative AI agents, complex workflows (e.g., tax filing, advisory, audit), and document‑centric experiences.
* Build and evolve AI orchestration: routing, tool calling, MCP servers, multi‑step workflows, safety and guardrails, and robust error handling around third‑party LLMs (OpenAI, Anthropic, and others).
** Scale, reliability, and performance
*** Design for high‑throughput, low‑latency AI workloads: caching, queuing, rate‑limiting, model failover, and cost/performance tradeoffs.
* Work with large‑scale data: millions of documents, retrieval and search, vector stores, and indexing strategies tailored to tax and accounting use cases.
* Establish and refine SLOs, observability, and incident response for AI systems that must be correct, auditable, and trustworthy in professional workflows.
*
* About You:

** You are a fit for the position of
** Principal Software Engineer,AI
** if your background includes:
* Bachelors Degree in Computer Science, Computer Engineering, Related Field, or Equivalent Experience
* ** 8-10+ years of experience in backend development**, building scalable web services and APIs.
* Deep
**…