Harvey AI vs Spellbook: Enterprise Platform vs Word Add-In

Harvey AI is a full-stack enterprise legal AI platform at $150–300/seat/month. Spellbook is a focused contract drafting tool at $99/user/month that lives inside Microsoft Word. Harvey raised $206M+ from Sequoia and Google Ventures to build an all-in-one legal AI. Spellbook raised $20M+ to do one thing well: make contract drafting faster without changing how lawyers work.

This comparison illustrates the fundamental choice in legal AI adoption: platform vs. point solution. Harvey asks you to adopt a new system. Spellbook fits into your existing one. The right answer depends on your firm's size, budget, and willingness to change workflows.

Feature Comparison

Harvey AI covers legal research, contract review, deposition prep, due diligence workflows, and custom training on firm data. It's a platform — you go to Harvey to do legal work. The scope is broad: research, drafting, analysis, and document review across practice areas.

Spellbook covers contract drafting suggestions, clause libraries, risk flagging, contract review with suggested edits, and custom playbook creation — all inside Microsoft Word as a native add-in. The scope is narrow but deep: contracts only, but with firm-specific playbooks that encode YOUR standard positions.

Pricing and Cost

Harvey AI: $150–300/seat/month, enterprise annual contracts, seat minimums. A 10-attorney transactional team costs $18K–36K/year.

Spellbook: $99/user/month with annual billing discounts. The same 10-attorney team costs $11,880/year.

Spellbook is 33–67% cheaper and doesn't require enterprise contracts or seat minimums. For transactional practices that primarily need contract drafting AI, Spellbook delivers the most relevant capability at a lower price. Harvey's premium only makes sense if you also need research, deposition prep, and other capabilities beyond contracts.

Data Privacy and Compliance

Harvey AI: SOC 2 Type II, enterprise data agreements, no training on client data. Custom training on firm data creates additional data handling considerations.

Spellbook: SOC 2 Type II, no training on client documents, data encrypted at rest and in transit. Simpler data footprint because it's a Word add-in, not a standalone platform.

Both meet enterprise security requirements. Spellbook's simpler architecture means fewer data handling questions during compliance review. Harvey's custom training feature requires more detailed data governance policies.

Best For

Choose Harvey AI if your firm needs AI across multiple practice areas and use cases — research, drafting, document review, deposition prep. Harvey makes sense for large firms (50+ attorneys) with diverse practices that want a single AI platform across the organization.

Choose Spellbook if your firm's primary AI need is contract drafting and review. Solo practitioners, small to mid-size transactional firms, and in-house legal teams get immediate value from Spellbook at $99/month. The custom playbook feature — encoding your firm's standard positions — is a capability that Harvey's broader platform doesn't match for contract-specific work.

The Verdict

For transactional practices, Spellbook wins. It's cheaper, it works inside Word (zero workflow disruption), and the custom playbook feature is purpose-built for contract work. Harvey's broader capabilities are wasted if you primarily draft and review contracts.

For full-service firms, the calculation changes. Harvey covers more ground — but even then, consider Spellbook for the transactional team and Claude at $25/user/month for research and general analysis. That combination costs less than Harvey alone and gives each practice group a tool optimized for their actual work.

The lock-in difference matters too. Spellbook's low lock-in risk (Word add-in, monthly billing possible) means you can try it with minimal commitment. Harvey's high lock-in (annual contracts, seat minimums, firm-specific training) means the exit cost grows over time.

The Bottom Line: Spellbook wins for transactional practices at $99/month with zero workflow disruption; Harvey wins only for full-service firms that need AI across multiple practice areas and can justify 2-3x the cost.