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Harvey vs CoCounsel vs Legora Compared

By Mark Fulton5 min read
Harvey vs CoCounsel vs Legora Compared

When a large firm or serious in-house team shortlists an AI legal platform in 2026, three names keep coming up: Harvey, CoCounsel, and Legora. All three do research, drafting, and document analysis. All three sell to law firms and in-house teams. And all three gate pricing behind a demo, which makes public comparison harder than it should be.

We don't sell any of them, so here's the comparison as we see it — built from what each platform verifiably is, not from a vendor's battle card.

The one difference that matters most: grounding

The deepest split between these platforms is what the AI's answers are grounded in.

CoCounsel is Thomson Reuters' assistant, and its defining trait is that it answers from Westlaw and Practical Law content. When it handles a research memo, document review, deposition prep, or drafting task, it's working against the same editorial database your firm already trusts (and probably already pays for). CoCounsel started life at Casetext, which Thomson Reuters acquired in 2023 — one of the moves that kicked off the current consolidation wave we track in the acquisition tracker.

Harvey and Legora are platform-agnostic. Neither is tied to a single publisher's research database; both are built as workbenches over your documents and workflows. That's a real tradeoff, not a defect on either side: CoCounsel's grounding gives you a known citation backbone; the platform-agnostic pair give you freedom from a single vendor's content ecosystem.

If your evaluation starts anywhere, start there — it's the difference that won't change with the next model release.

Grounding reduces hallucination. It does not eliminate it.

This is the single most important caveat in the category, and it's now measured rather than argued.

Stanford's RegLab and Institute for Human-Centered AI evaluated the leading retrieval-grounded legal research tools across 202 queries, hand-scored by legal experts, in Hallucination-Free? Assessing the Reliability of Leading AI Legal Research Tools (peer-reviewed in the Journal of Empirical Legal Studies, 2025). The findings:

Tool Hallucination rate What the vendor claimed
Lexis+ AI 17% "100% hallucination-free linked legal citations"
Westlaw AI-Assisted Research 33% Tools "avoid hallucinations by relying on trusted content"

Both of those products are grounded in exactly the kind of curated editorial database that CoCounsel's pitch rests on — and Westlaw AI-Assisted Research is Thomson Reuters' own. The researchers concluded that providers' claims are overstated.

Read the grounding split above as a difference in citation backbone and vendor lock-in, not as a guarantee of correctness. Any of these platforms can produce a confident wrong answer, which is why ABA Formal Opinion 512 makes understanding a tool's propensity to hallucinate part of the duty of competence. Budget for verification in every ROI model you build.

The practical version of that budget is an evaluation loop: a fixed set of representative queries with known-good answers, re-run whenever the vendor ships a model update, so a quality regression shows up in your pilot rather than in a filing. Reinventing.AI Insights covers how to build one of those loops for AI agents generally; the mechanics transfer directly to a legal platform pilot.

What each platform actually is

Harvey is an AI platform for law firms and professional services teams covering research, drafting, and document analysis, with agents built for specific practice areas. That agent orientation is the direction of travel: less "chat with a model," more delegated multi-step work. Harvey is also expanding by acquisition — it bought workflow startup Hexus in January 2026.

CoCounsel is the productized assistant: research memos, document review, deposition preparation, and drafting, all grounded in the Thomson Reuters stack. If your lawyers live in Westlaw, it's the shortest path to AI that fits existing habits.

Legora is the collaborative workspace of the three — agentic research, tabular review across sets of documents, and a Microsoft Word add-in. It was founded in Stockholm as Leya and rebranded to Legora in 2025, and is used by both law firms and in-house teams. The tabular review pattern — running the same questions across many documents and getting a structured grid back — is the feature that most differentiates the demo.

Pricing: all demo-gated

None of the three publishes pricing. That's the honest answer, and any article quoting exact figures for these platforms is either citing a private quote or making it up. Budget expectations should come from your own demo process — and if published pricing matters to you on principle, Paxton publishes a rate ($499/user/month) in the same research-and-drafting space, and we keep a list of verified free and low-cost tools at the other end of the market.

How to choose between them

Choose CoCounsel if your firm's research life already runs through Westlaw and Practical Law. The grounding does real work: citations trace back to an editorial database your partners already accept, which shortens the internal trust battle that sinks many AI rollouts.

Choose Harvey if you're buying a platform strategy rather than a product — practice-area agents, document analysis, and drafting under one roof, with a vendor that's visibly assembling more of the workflow (the Hexus acquisition being the latest evidence).

Choose Legora if the way your teams work is collaborative and document-heavy: shared workspaces, tabular review across large document sets, and lawyers who want the AI inside Word rather than in a separate tab.

And in all three cases: run the pilot on your own matters, with your own documents, scored by the lawyers who'd use it daily. These platforms differ most under real workload, which is exactly the part a demo controls.

The caveats a vendor comparison would skip

  • All three claims above are structural, not benchmark results. We're comparing what the platforms verifiably are — grounding, scope, ownership — not asserting which produces better answers on your matters. Only your pilot can tell you that.
  • Ownership is in motion. CoCounsel already changed hands once (Casetext → Thomson Reuters). Harvey is acquiring. Legora has already rebranded once (Leya → Legora). None of that is disqualifying — it's just the market — but sign contracts with the consolidation wave in mind.
  • The shortlist shouldn't always be three. Depending on the actual bottleneck, a research specialist like Midpage or Alexi, or a contract-focused tool, may beat a platform purchase entirely.

All three platforms — and 32 more — are listed in the directory, free and verified, with no vendor input on how any of this was written.

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