Software Engineer - AI Platform

Thomson Reuters is building the AI platform that will power the next decade of tax, accounting and audit products, including CoCounsel Audit, a suite of AI‑native products used by accountants on real client work every day. As a Lead Software Engineer (Staff 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 Audit team, formed from the recent acquisition of the startup Materia.

You will be a Lead Software Engineer (Staff Engineer) responsible for the backend and orchestration layer powering AI agents, conversations, work spaces, and knowledge base across CoCounsel for Audit.

• Shape the team'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 your product area and adjacent teams, not just a single feature.
• Shape the platform integration strategy across new and existing Thomson Reuters audit systems to provide world‑class content and solutions for our customers.
• 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 people who enjoy and thrive at setting technical direction, mentoring senior engineers, and spending most of the time in the code and architecture of AI systems.

• 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 senior and mid‑level engineers, raising the bar on system design, code quality, and AI integration practices across the org.
• Be a go‑to 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 post‑mortems.

• Provide your technical POV on architecting and implementing backend services (Python, FastAPI, PostgreSQL, 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).

• Design for high‑throughput, low‑latency AI workloads: caching, queuing, rate‑limiting, model failover, and cost/performance trade‑offs.
• 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.

You are a fit for the position of Lead Software Engineer (Staff Engineer) if your background includes:

• Bachelor's degree in computer science, computer engineering, a related field, or equivalent experience.
• 5–7+ years of experience in full‑stack development, building scalable cloud‑based applications, web services, APIs and AI‑driven products.
• Deep Python expertise and experience with production systems using frameworks like FastAPI (or similar), relational databases (PostgreSQL or equivalent), and a major cloud provider (AWS preferred).
• Strong background in distributed systems: data modeling, API contracts, observability, resilience patterns, and performance tuning under load.
• Proven track record leading large, complex projects…