Principal Engineer CoCounsel Audit

This posting is for proactive recruitment purposes and may be used to fill current openings or future vacancies within our organization.

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 AInative 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 productiongrade workflows at scale.

This role is for the CoCounsel for Audit team formed from the recent acquisition of the startup Materia.

About the role:

Own the AI backbone: You will be the principal engineer responsible for the backend and orchestration layer powering AI agents conversations workspaces and knowledge base across CoCounsel for Audit.

• Shape the companys 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 timesensitive 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 highimpact IC track. You keep the scope and influence of an EM driving multiteam 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.

What youll do:

Technical leadership and crossfunctional influence

• Lead multiquarter 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 userfacing workflows that accountants trust.

• Help shape the teams roadmap technical strategy and engineering culture from experimentation practices to testing rollout and postmortems.

• Help define and lead the platform integration strategy across new and existing Thomson Reuters audit systems to provide world class content and solutions for our customers.

Design and own AIfirst backend systems

• Architect and implement backend services (Python FastAPI PostgreSQL AWS Vercel) that power generative AI agents complex workflows (e.g. tax filing advisory audit) and documentcentric experiences.

• Build and evolve AI orchestration: routing tool calling MCP servers multistep workflows safety and guardrails and robust error handling around thirdparty LLMs (OpenAI Anthropic and others).

Scale reliability and performance

• Design for highthroughput lowlatency AI workloads: caching queuing ratelimiting model failover and cost/performance tradeoffs.

• Work with largescale 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 if your background includes:

Required Experience & Skills:

• 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 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 owning large complex projects endtoend: architecture execution rollout and longterm operation.

• Excellent communication skills and the ability to partner with product design and ML teams in a fastmoving environment.

• Demonstrated interest in AI systems and new engineering paradigms: LLMs agents retrieval or similar you care about what AInative software should look like.

Preferred Skills & Experience

• Handson experience integrating LLM APIs (e.g. OpenAI Anthropic) into production applications including prompt/response management cost controls and safety considerations.

• Experience with AIadjacent 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 or similar) or strong interest in applying AI in those contexts.

• Many of our strongest candidates have bounced between EM and senior IC roles. If youve been managing for the last few years and want to get closer to the hard technical problems again without giving up scope or career progression this principal IC role is built for that pivot.

#LI-TH1

Whats in it For You

• Hybrid Work Model: Weve adopted a flexible hybrid working environment (2-3 days a week in the office depending on the role) for our office-based roles while delivering a seamless experience that is digitally and physically connected.

• Flexibility & Work-Life Balance: Flex My Way is a set of supportive workplace policies designed to help manage personal and professional responsibilities whether caring for family giving back to the community or finding time to refresh and reset. This builds upon our flexible work arrangements including work from anywhere for up to 8 weeks per year empowering employees to achieve a better work-life balance.

• Career Development and Growth: By fostering a culture of continuous learning and skill development we prepare our talent to tackle tomorrows challenges and deliver real-world solutions. Our Grow My Way programming and skills-first approach ensures you have the tools and knowledge to grow lead and thrive in an AI-enabled future.

• Industry Competitive Benefits: We offer comprehensive benefit plans to include flexible vacation two company-wide Mental Health Days off access to the Headspace app retirement savings tuition reimbursement employee incentive programs and resources for mental physical and financial wellbeing.

• Culture: Globally recognized award-winning reputation for inclusion and belonging flexibility work-life balance and more. We live by our values: Obsess over our Customers Compete to Win Challenge (Y)our Thinking Act Fast / Learn Fast and Stronger Together.

• Social Impact: Make an impact in your community with our Social Impact Institute. We offer employees two paid volunteer days off annually and opportunities to get involved with pro-bono consulting projects and Environmental Social and Governance (ESG) initiatives.

• Making a Real-World Impact:We are one of the few companies globally that helps its customers pursue justice truth and transparency. Together with the professionals and institutions we serve we help uphold the rule of law turn the wheels of commerce catch bad actors report the facts and provide trusted unbiased information to people all over the world.

Our use of AI within the recruitment process Thomson Reuters utilizes Artificial Intelligence (AI) to support parts of our global recruitment process. Unless you opt-out our AI system will assess the information provided by you and compare it to the requirements listed for the role and present the result to our recruitment personnel for further review. The AI system acts as a supporting tool but there is always a human making the decision if you will be considered for the role.

In the United States Thomson Reuters offers a comprehensive benefits package to our employees. Our benefit package includes market competitive health dental vision disability and life insurance programs as well as a competitive 401k plan with company addition Thomson Reuters offers market leading work life benefits with competitive vacation sick and safe paid time off paid holidays (including two company mental health days off) parental leave sabbatical leave. These benefits meet or exceeds the requirements of paid time off in accordance with any applicable state or municipal laws. Finally Thomson Reuters offers the following additional benefits: optional hospital accident and sickness insurance paid 100% by the employee; optional life and AD&D insurance paid 100% by the employee; Flexible Spending and Health Savings Accounts; fitness reimbursement; access to Employee Assistance Program; Group Legal Identity Theft Protection benefit paid 100% by employee; access to 529 Plan; commuter benefits; Adoption & Surrogacy Assistance; Tuition Reimbursement; and access to Employee Stock Purchase Plan.

Thomson Reuters complies with local laws that require upfront disclosure of the expected pay range for a position. The base compensation range varies across locations. Eligible office location(s) for this role include one or more of the following: New York City San Francisco Los Angeles and/or Irvine CA; McLean VA; Washington DC. The base compensation range for the role in any of those locations is $183100 USD - $340000 USD. For any eligible US locations unless otherwise noted the base compensation range for this role is $158900 USD - $295100 USD. Base pay is positioned within the range based on several factors including an individuals knowledge skills and experience with consideration given to internal equity. Base pay is one part of a comprehensive Total Reward program which also includes flexible and supportive benefits and other wellbeing programs. This role may also be eligible for an Annual Bonus based on a combination of enterprise and individual performance.

About Us

Thomson Reuters informs the way forward by bringing together the trusted content and technology that people and organizations need to make the right decisions. We serve professionals across legal tax accounting compliance government and media. Our products combine highly specialized software and insights to empower professionals with the data intelligence and solutions needed to make informed decisions and to help institutions in their pursuit of justice truth and transparency. Reuters part of Thomson Reuters is a world leading provider of trusted journalism and news.

We are powered by the talents of 26000 employees across more than 70 countries where everyone has a chance to contribute and grow professionally in flexible work environments. At a time when objectivity accuracy fairness and transparency are under attack we consider it our duty to pursue them. Sound exciting Join us and help shape the industries that move society forward.

As a global business we rely on the unique backgrounds perspectives and experiences of all employees to deliver on our business goals. To ensure we can do that we seek talented qualified employees in all our operations around the world regardless of race color sex/gender including pregnancy gender identity and expression national origin religion sexual orientation disability age marital status citizen status veteran status or any other protected classification under applicable law. Thomson Reuters is proud to be an Equal Employment Opportunity Employer providing a drug-free workplace.

Thomson Reuters makes reasonable accommodations for applicants with disabilities including veterans with disabilities and for sincerely held religious beliefs in accordance with applicable law. If you reside in the United States and require an accommodation in the recruiting process you may contact our Human Resources Department at. Disability accommodations in the recruiting process may include things like a sign language interpreter making interview rooms accessible providing assistive technology or other relevant accommodations. Please note this email is not intended for general recruitment questions and we will promptly respond to inquiries regarding accommodations. More information on requesting an accommodation here.

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