Dioptra vs Spellbook (2026): Pricing, Features & Which to Choose

Who comes out ahead

Based only on the facts in our directory. The right pick still depends on the job you need done.

Lower starting price
Not comparable
Not comparable: Dioptra does not list a price
Free plan
Tie
Neither has one
Higher rating
Spellbook
3.7 against 4.2
Same job?
Yes
Both are Legal AI tools

Side by side

Compared on	Dioptra	Spellbook
Our rating	3.7	4.2Better
Starts at	Not listed	Not listed
Free plan	No	No
Category	Legal AI	Legal AI
Plans	See pricing	See pricing
Key features	AI redlining driven by your own playbooks Learns from previously executed contracts Marks up against your accepted positions, not generic standards Published pricing and self-serve signup Demo path for evaluation	Drafts contract language and flags risky clauses directly inside Microsoft Word Purpose-built for transactional contract drafting and negotiation No separate platform to learn, works inside an existing document editor $63M total funding including a $50M Series B in October 2025 Originally founded in 2017, rebranded around the Spellbook product in 2022
Pros	Redlining against your executed contracts beats generic template comparison Playbook-driven, so it encodes positions your team already holds Pricing and signup published rather than sales-gated	Works directly inside Microsoft Word, no new platform to adopt Focused specifically on contract drafting, a clear and narrow job to be done Recent substantial funding from a top-tier investor
Cons	Recently acquired by Icertis - ask about roadmap and integration before a long commitment Requires a body of executed contracts and playbooks to work well Redlines inform a lawyer's judgement, they do not replace it	Narrower scope than full-platform competitors, doesn't cover research or due diligence Word-native workflow requires a firm already standardized on Microsoft's document tools Smaller funding scale than Harvey or Legora limits comparable investment pace
Company	Dioptra (Icertis)	Spellbook, founded 2017

Prices come from each vendor's pricing page, last checked 20260901. Check the vendor before you buy.

FAQ

Questions people ask

Is Dioptra better than Spellbook?

In our reviews Dioptra scores 3.7 and Spellbook scores 4.2. The better pick depends on the job. Dioptra: AI contract redlining that works from your own playbooks and previously executed contracts, rather than generic legal templates. Spellbook: Drafts and redlines contracts directly inside Microsoft Word.

Which is cheaper, Dioptra or Spellbook?

Dioptra: see pricing. Spellbook: see pricing.

Do Dioptra and Spellbook have free plans?

Neither lists a free plan.

More comparisons

Dioptra compared with

All Dioptra alternatives

Spellbook compared with

All Spellbook alternatives