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Principal Engineer

Thomson Reuters
United StatesRemotefull_timeVerifiedPosted 22 Jul 2026
💰 $340,000/yr($183,100/yr$340,000/yr)

About the role

Principal Software Engineer – CoCounsel 
 
CoCounsel is our most advanced AI offering to date – combining generative and agentic AI capabilities to help legal professionals move beyond prompting and start delegating.  As a Principal Software Engineer, you will set the technical direction for the backend, AI orchestration, and identity systems that turn frontier models into reliable, secure, production-grade workflows that attorneys, in-house legal departments, and government agencies trust on real client matters every day. 

This role sits at the heart of the CoCounsel Legal engineering organization, partnering closely with AI/ML engineers, researchers, product, and our identity and platform teams to deliver world-class legal content and AI experiences at scale. 

About the role: 

In this opportunity as a Principal Engineer, you will:

  • Own identity and trust at the core: Set the direction for how users, agents, and services authenticate and authorize across CoCounsel Legal – ensuring the right person and the right agent can access the right matter, document, and content, with full auditability.  Own the design and evolution of authentication and authorization across CoCounsel Legal – considering roles, autonomous agents, etc.. Partner with security, platform, and compliance teams on multi-tenancy isolation, data residency, privilege protection, and the audit trails that legal and government customers require Partner with security, platform, and compliance teams on multi-tenancy isolation, data residency, privilege protection, and the audit trails that legal and government customers require. 

  • 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. 

  • Technical leadership and cross-functional influence:  Lead and/or design initiatives that cut across AI, product, identity, and infrastructure Mentor staff and senior engineers, raising the bar on AI integration practices, system design, code quality, and security 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 legal professionals trust.  Help shape the team’s roadmap, technical strategy, and engineering culture – from experimentation practices to testing, rollout, and postmortems.   

  • Scale, reliability, and performance:  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 legal use cases.  Establish and refine SLOs, observability, and incident response for AI systems that must be correct, auditable, and trustworthy in professional legal workflows. 

About You: 

You are a fit for the position of Principal Software Engineer if your background includes: 

  • Bachelor’s Degree in Computer Science, Computer Engineering, a related field, or equivalent experience. 

  • Hands-on experience with identity and access management – designing or integrating authentication and authorization at scale (SSO, SAML, OIDC, OAuth 2.0, RBAC/ABAC, token/session management, or comparable IAM systems).

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Thomson Reuters

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