If you're evaluating legal AI tools for your firm, Harvey and Spellbook will come up on almost every shortlist. They're two of the most talked-about names in the space right now. But here's the thing: they're not really competing for the same firms.
Harvey is built for large law firms and sophisticated in-house legal teams doing complex, high-volume work. Spellbook is built for contract-focused attorneys who work primarily in Microsoft Word and want AI assistance without disrupting how they already practice. Understanding which category your firm falls into makes this decision much cleaner.
The core difference, in plain English
Harvey is an enterprise legal AI platform for research, drafting, and analysis — built on Azure OpenAI infrastructure with a custom-trained model developed in partnership with OpenAI, designed for complex legal work at scale. Spellbook is an AI contract drafting assistant powered by GPT-4o that lives inside Microsoft Word.
That distinction sounds simple. But it shapes everything about how each tool is deployed, who uses it daily, and what kind of value it actually delivers.
Harvey is a platform you integrate into your firm's technology stack. It requires deployment, coordination with IT, and onboarding. Firms report it excels at legal research, memo drafting, regulatory analysis, and complex document work. Spellbook is an add-in you install in Word in minutes. It shows up as a sidebar, reads your contract as you write it, and makes AI-powered suggestions in context. The learning curve is low and adoption happens fast.
Who Harvey is actually built for
Harvey has built its reputation at Am Law 100 firms and large in-house legal teams. The platform is built on Azure OpenAI infrastructure with a custom-trained model developed in partnership with OpenAI — designed to reason specifically about legal knowledge rather than general-purpose tasks. Harvey reached approximately an $8 billion valuation in a December 2025 Series F round.
Complex legal research at volume
Harvey is known for strong performance on legal research tasks — case law analysis, regulatory interpretation, statutory review. For firms where attorneys spend significant time on research, the productivity gains firms report can be meaningful.
A broader product suite: Assistant, Vault, and Workflow Builder
Harvey's platform goes beyond a single AI assistant. Vault is built for parking and reviewing large document sets. Workflow Builder automates multi-step legal tasks. Microsoft 365 integrations mean the AI can work closer to where attorneys already operate.
Ethical wall enforcement and auditable AI use
Harvey partners with Intapp for ethical wall enforcement, making firm-wide AI use permissioned and auditable across client matters. This is a meaningful feature for firms managing conflicting representations and attorney-client privilege obligations — an area most legal AI platforms handle less explicitly.
Large enterprise and in-house deployments
Harvey is built to work at enterprise scale. For large in-house legal teams managing significant contract volume, regulatory work, or litigation support, the platform is designed to handle that load.
Firms that can invest in deployment and onboarding
Harvey is not a self-serve tool. It requires IT involvement, procurement, and a real implementation process. Firms that are prepared for that investment tend to get more out of it.
Who Spellbook is actually built for
Spellbook is designed for contract-focused attorneys — lawyers who do most of their work in Microsoft Word, negotiating agreements, reviewing terms, and drafting clauses. Powered by GPT-4o, it meets attorneys exactly where they already are. More than 4,000 law firms and in-house teams use it.
Contract lawyers who live in Word
Spellbook runs on GPT-4o and works as a Word add-in. Attorneys draft as they normally would, and Spellbook reads the document in real time, surfacing suggestions, flagging missing clauses, and offering negotiation-aware redlines. There is no new platform to learn.
Firms with strict data privacy requirements
Spellbook operates a zero data retention policy — documents are never stored or used to train AI models. The platform is SOC 2 Type II, GDPR, and CCPA compliant. For firms where attorney-client privilege and client confidentiality are top concerns, zero retention means uploaded documents leave no trace after a session.
Transactional practices focused on contract volume
Spellbook benchmarks contract language against more than 2,000 industry standards and flags deviations from market norms. The company also offers Spellbook Associate, an agent product for more complex multi-step contract workflows.
Firms that want to evaluate before committing
Spellbook offers a 7-day free trial — you can test it in real workflows on real documents before a procurement conversation. This is a meaningful contrast to most legal AI tools, which require a demo-to-contract process before you can validate fit.
Pricing: what you can expect
Pricing is one of the biggest differentiators between these two tools. It's worth being direct about it.
Harvey does not publicly list pricing. Pricing is enterprise-negotiated and varies based on firm size, usage volume, and deployment requirements. Contact vendor for pricing.
Enterprise contracts only. No self-serve tier.
Spellbook offers per-seat plans for firms of all sizes and a 7-day free trial — the only major legal AI tool you can evaluate without a sales conversation first. Industry estimates put mid-tier plans at approximately $179 per user per month, though pricing is quote-based and varies by team size. Contact vendor for current pricing.
Per-seat plans. 7-day free trial available. No enterprise procurement required.
The pricing gap between these tools is real and it matters for your evaluation. If your firm has an enterprise procurement process and a meaningful legal tech budget, Harvey is worth a serious conversation. If your firm wants to get started with legal AI without a lengthy contract cycle, Spellbook is the faster path.
What each tool doesn't do
This is the part of most tool comparisons that gets glossed over. It matters.
Harvey is not the right fit if:
- Your firm is under 50 attorneys and doesn't have an IT team to support a deployment
- Your primary need is contract drafting in Word — Harvey is broader than that, but Spellbook is more focused
- Your budget doesn't support enterprise software contracts
Spellbook is not the right fit if:
- Your primary need is legal research — Spellbook is focused on contracts, not case law analysis
- You need litigation support or brief writing assistance at scale
- Your team needs enterprise-grade document review or due diligence capabilities
What about CoCounsel and Lexis+ AI?
If your firm is already running on Westlaw or LexisNexis, there's a strong case to consider CoCounsel or Lexis+ AI before either Harvey or Spellbook. Both tools are built to extend platforms your attorneys are already using every day. One recent development worth noting: LexisNexis rebranded Lexis+ AI to “Lexis+ with Protégé” in February 2026, reflecting expanded AI capabilities including access to both Anthropic and OpenAI models.
I've sold CoCounsel directly to attorneys and law firms through my time at Thomson Reuters. What made it compelling in those conversations wasn't just the AI — it was that it sat directly on top of Westlaw, a tool attorneys already trusted for research. That integration removes a meaningful adoption barrier. Thomson Reuters has since expanded CoCounsel significantly: it now draws on multiple frontier AI models including Anthropic's Claude, OpenAI's GPT, and Google's Gemini alongside proprietary Thomson Reuters technology, and recently launched CoCounsel Legal with agentic AI and deep research capabilities. The platform has surpassed one million users across more than 100 countries.
If your firm is research-heavy and already embedded in either the Westlaw or LexisNexis ecosystem, evaluating those platforms alongside Harvey and Spellbook is worth the extra time. Our full Legal AI overview covers all six tools in detail.
What most legal AI comparisons miss
Most tool comparisons stay at the surface — features, pricing, use cases. Here are four things worth digging into before your firm commits to either platform.
Which AI model is actually processing your documents?
Harvey is built on Azure OpenAI infrastructure with a custom-trained model developed in partnership with OpenAI. Spellbook uses GPT-4o. Both tools process your documents through OpenAI-based infrastructure. If your firm has a corporate IT policy restricting which AI providers can touch client data — or if you're evaluating tools for matters where data residency matters — ask vendors specifically about their infrastructure and subprocessor agreements before you sign.
What happens to your documents after you upload them?
Spellbook operates a zero data retention policy — documents are never stored or used to train AI models. For Harvey, data handling is governed by enterprise contract terms and includes ethical wall enforcement through a partnership with Intapp, making firm-wide AI use permissioned and auditable across client matters. For any tool you evaluate, ask: is my data used to improve the model? Can data from one client matter be accessed in the context of another?
Can you actually try it before you buy?
Spellbook offers a 7-day free trial — you can evaluate it in real workflows on real documents without a sales conversation. Harvey does not; it requires enterprise procurement. Being able to validate a tool in your actual environment before committing changes what you can know before you sign. A polished demo is not the same as testing on your firm's actual contracts.
Where exactly does the AI work in your attorneys' day?
Spellbook lives inside Word — it's where your contract attorneys already are. Harvey has Microsoft 365 integrations and its own web-based interface. The question worth asking any vendor is: does this tool work where my attorneys actually spend their time, or does it require switching to a new application? The answer affects how quickly your team will adopt it and how much value you'll actually realize.
Final take: how to decide
The decision between Harvey and Spellbook comes down to two questions: what kind of work does your team do most, and how much infrastructure are you prepared to invest?
If your firm does complex research, litigation support, or regulatory work at volume — and has the IT resources and budget for an enterprise deployment — Harvey is worth a serious evaluation. Firms that work with Harvey report it as genuinely capable for high-stakes legal work.
If your firm's attorneys spend most of their time drafting and negotiating contracts in Word, and you want to see meaningful AI value quickly without a long implementation cycle, Spellbook is the cleaner path. It meets your team where they already are and gets out of the way.
And if you're genuinely uncertain about which category of legal AI fits your practice, our five-question assessment will help you narrow it down, including tools beyond just these two.
