CoCounsel vs Westlaw: pricing, features and which to choose

CoCounsel is a professional legal AI assistant made by Thomson Reuters and descended from Casetext's product of the same name. Casetext launched CoCounsel in March 2023, and Thomson Reuters announced a $650 million acquisition of Casetext that year. The product now sits across Thomson Reuters' legal portfolio rather than operating as an independent Casetext service. Thomson Reuters said in February 2026 that one million professionals across 107 countries and territories had chosen CoCounsel across legal, tax, audit, compliance, and related products. Legal users are the clearest audience, including litigators, transactional lawyers, in-house teams, and firms that already buy Westlaw or Practical Law. The acquisition brought Casetext's product expertise into Thomson Reuters, while the current offering adds licensed content and broader distribution.

A typical workflow starts with a natural-language request, an uploaded file, a connected document repository, or a Thomson Reuters research collection. Users can summarize and compare documents, extract information, identify missing provisions, prepare deposition materials, build timelines, draft text, and check contract policies. Knowledge Search can find material in a firm's own repositories, while Browse Library exposes expert-built prompts and skills. Agentic workflows handle multi-step assignments, and Deep Research gathers and synthesizes authority for a more complete answer. Outputs are designed to include citations or links where selected content supports them, but lawyers still need to check quotations, authorities, privilege, confidentiality, and final work product before relying on it. The system assists legal judgment rather than replacing professional review.

CoCounsel's strongest case is a research-heavy practice already invested in Thomson Reuters content. Its citations, document skills, repository connections, Microsoft 365 integrations, and agentic workflows can reduce switching between research and drafting tools, though outputs remain subject to legal review. Law firms should compare it with Harvey, Lexis+ AI, and Legora rather than assume the content advantage settles the decision. Independent 2025 benchmarking placed CoCounsel among the stronger tools across document tasks, while Law360 reported that some early adopters preferred Harvey or Legora for interface and workflow reasons. Privacy terms prohibit using customer prompts and content to train third-party models, with configurable retention, encryption, and zero-retention model APIs. Choose CoCounsel when Westlaw or Practical Law is central and authoritative citations matter most.

Westlaw is Thomson Reuters’ subscription legal research platform for law firms, corporate legal departments, government users, and law schools. Its history reaches back to 1975, and Thomson Reuters says Westlaw Edge launched in 2018 as an AI-driven search product. The current US flagship offer is Westlaw Advantage, which combines Westlaw content with agentic AI and litigation tools. Thomson Reuters continues to use Westlaw as the product and database brand, while Edge remains in some regional and legacy materials. The service is built around primary law, secondary sources, editorial enhancements, headnotes, citators, and jurisdiction-specific coverage. It is a professional subscription rather than a consumer legal information service. This positioning means usefulness depends heavily on the jurisdictions, practice areas, and content collections included in an account.

A typical researcher enters a natural-language or Boolean query, reviews ranked authorities, and opens linked cases, statutes, regulations, or secondary sources. Headnotes and the West Key Number System help users move from one decision to related authorities. KeyCite shows cited treatment and connections across the research record. Westlaw Edge adds search assistance, analytics, and AI-assisted research. Thomson Reuters describes a workflow in which a user asks a question conversationally, receives an overview with supporting language, and opens linked authority for review. Current Advantage materials list Deep Research, Litigation Document Analyzer, Claims Explorer, AI Jurisdictional Surveys, statutes and regulations comparison, and litigation analytics. Availability varies by plan and jurisdiction. Teams should therefore confirm that desired tools are enabled before treating the platform as a complete workflow.

Westlaw’s editorial depth and KeyCite workflow are useful for teams that must verify authority, but contract terms and coverage choices make comparisons difficult. Lexis+ AI is the closest direct competitor, Bloomberg Law is strong for US research, dockets, and litigation workflow, and vLex offers broad international content with AI search. Generative answers require professional review, and Westlaw is neither open source nor self-hostable. Thomson Reuters does not advertise a general consumer tier or a public self-service developer database. Its strongest fit is an established legal research environment where editorial reliability and citator depth justify subscription expense, rather than a lightweight tool for occasional public legal information searches. Choose Westlaw for professional legal teams that need established West content, cited-treatment research, and AI features tied to linked authority.