About the role Thomson Reuters is building the AI platform that will power the next decade of tax, accounting and audit products, including CoCounsel Audit. As a Principal Software Engineer for the CoCounsel for Audit team (formed from the acquisition of Materia), you will own core backend and AI orchestration systems that turn frontier models into reliable, production‑grade workflows at scale. Responsibilities Own the AI backbone: principal engineer responsible for the backend and orchestration layer powering AI agents, conversations, workspaces, and the knowledge base across CoCounsel for Audit. Shape the company’s AI platform and patterns: define patterns for building MCP servers, designing agents, novel uses of LLMs, experimentation, and scalable infrastructure. 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. Join a tight group of senior engineers and researchers shipping quickly, with direct access to product leadership and customers. Intended for senior engineers and engineering managers who want to move back to an high‑impact IC track while maintaining scope and influence. Technical leadership and cross‑functional influence Lead multi‑quarter initiatives cutting 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, translating industry improvements into reliable, user‑facing workflows that accountants trust. Help shape the team’s roadmap, technical strategy, and engineering culture. Define and lead platform integration strategy across new and existing Thomson Reuters audit systems. Design and own AI‑first backend systems Architect and implement backend services (Python, FastAPI, PostgreSQL, AWS, Vercel) powering generative AI agents, complex workflows (tax filing, advisory, audit), and document‑centric experiences. Build and evolve AI orchestration: routing, tool calling, MCP servers, multi‑step workflows, safety and guardrails, robust error handling around third‑party LLMs. Scale, reliability, and performance Design for high‑throughput, low‑latency AI workloads: caching, queuing, rate‑limiting, model failover, 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. About You Required Experience & Skills: Bachelor’s 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 Python expertise and experience with production systems using frameworks like FastAPI and relational databases such as PostgreSQL. Strong background in distributed systems: data modeling, API contracts, observability, resilience patterns, and performance tuning under load. Proven track record owning large, complex projects end‑to‑end. Excellent communication skills and the ability to partner with product, design, and ML teams. Demonstrated interest in AI systems and new engineering paradigms: LLMs, agents, retrieval, or similar. Preferred Skills & Experience Hands‑on experience integrating LLM APIs (OpenAI, Anthropic) into production applications, including prompt/response management, cost controls, and safety considerations. Experience with AI‑adjacent infrastructure: vector databases, embeddings, semantic search, or custom retrieval pipelines. Opinions and experience around automated testing, reliability, and release practices for systems with nondeterministic model behavior. Prior experience in domains where correctness, auditability, and compliance matter (fintech, tax, audit, legal). Experience moving between engineering manager and senior IC roles, desiring a pivot back to technical depth. Benefits Hybrid Work Model: 2‑3 days a week in the office depending on the role, with seamless digital and physical connectivity. Flexibility & Work‑Life Balance: policies including work from anywhere for up to 8 weeks per year. Career Development and Growth: learning and skill development programs, mentorship, and growth opportunities. Industry Competitive Benefits: flexible vacation, two company‑wide Mental Health Days off, Headspace app access, retirement savings, tuition reimbursement, employee incentive programs, and resources for mental, physical, and financial wellbeing. Culture: commitment to inclusion, belonging, flexibility, and fast learning. Social Impact: two paid volunteer days off annually, pro‑bono consulting opportunities, ESG initiatives. Real‑World Impact: supporting justice, truth, and transparency through product offerings. Compensation: The base compensation range for this role varies by location from $158,900 to $340,000 USD. An annual bonus may also be eligible. Equal Employment Opportunity Thomson Reuters is an Equal Employment Opportunity Employer. We provide reasonable accommodations for applicants with disabilities and sincerely held religious beliefs in accordance with applicable law. #J-18808-Ljbffr