Luminance vs Spellbook: Enterprise Review or Word Drafting?
Choose Luminance if your problem is volume: a large flow of inbound contracts, an archive of signed ones you cannot search, or obligations spread across jurisdictions, and you have procurement and a budget to match. Choose Spellbook if your problem is the document open on your screen: a lawyer or small team drafting and redlining in Word who wants to be live this month on a per-seat plan. Both tools now run inside Microsoft Word, so "enterprise platform versus Word add-in" is no longer the clean split it used to be. The real difference is what each product is built around. Luminance is built around a contract estate, with review as one module among several. Spellbook is built around the drafter, with review, drafting and playbooks all inside the editing surface. Neither publishes a price. Below is what each does, where each wins, what the cost evidence actually supports, and a decision tree that sends you to Luminance, Spellbook, or a lighter tool with a published price.
This is software evaluation and industry analysis, not legal advice.
What does each tool actually do?
Luminance sells a platform of linked modules. Its own site describes three core areas: Negotiate for review and contract discussions, Discover for analysis across a contract portfolio, and Automate for workflow. Its Negotiate documentation states that it runs as a Microsoft Word add-in and can generate a first-pass redline from approved language, apply playbooks, and walk a reviewer through checklists of core negotiating positions. The company also describes ISO 27001 certification and regular SOC 2 Type II examinations, and says it serves more than 1,000 enterprises. Our Luminance pricing breakdown covers how the modules are packaged and sold.
Spellbook is an AI assistant for contract work, centred on Word. Its site lists review with tracked-change redlines, drafting of clauses and full agreements from templates or precedents, playbooks that encode team standards, a benchmark comparison against market terms, a question-and-answer feature, and a repository for signed contracts. It also lists integrations beyond Word, including Google Docs and several document management systems. The product description in our directory entry notes that it uses multiple large language models. Our Spellbook pricing breakdown covers what buyers report being quoted.
Put side by side, the overlap is real. Both redline in Word. Both apply playbooks. Both can do a first pass on third-party paper. The difference is gravity. Luminance pulls toward the repository and the department: your contracts, your obligations, your portfolio. Spellbook pulls toward the individual lawyer's editing session.
| Luminance | Spellbook | |
|---|---|---|
| Core shape | Platform of modules | Assistant in the editing surface |
| Works in Word | Yes, via the Negotiate add-in | Yes, its primary surface |
| Strongest at | Review at volume, portfolio analysis, workflow | Drafting and redlining one document at a time |
| Post-signature work | Portfolio analysis and obligation tracking modules | A repository with search and renewal monitoring |
| Pricing line in our directory | Pricing on request | Pricing on request |
| Sold how | Demo, scoping, custom quote, multi-year private offer | Demo, quote by team size, 7-day free trial |
| Typical buyer | In-house legal departments and larger firms | Transactional lawyers, law firms and in-house teams |
Where does Luminance's platform approach pay off?
It pays off when the unit of work is a set of contracts rather than one contract.
Large inbound queues. If your team receives a steady stream of third-party paper, supplier agreements, NDAs, sales terms, and a first-pass redline applied against your playbook is saving hours every week, throughput is what you are buying. The more contracts that flow through, the better the economics.
A signed archive you cannot query. The Discover module exists for the question "which of our 4,000 agreements has this clause, and when does it expire?" A drafting assistant is not built for that question. A platform with a repository and extraction layer is.
Cross-border and multi-team work. When legal, procurement and sales all touch contracts, a shared system with shared standards beats a licence held by individual lawyers. Luminance's workflow module is aimed at exactly that handoff.
Organizations that already run a procurement process. Enterprise contract software comes with security review, data terms and a negotiated term. If those processes exist, they are a cost already paid. If they do not, they are a cost added to the licence.
The trade-off is weight. A module platform asks you to scope, load data, configure playbooks and train users. For a team of four reviewing a few contracts a week, that is a lot of machinery around a small problem.
Where does Spellbook's Word workflow win?
It wins when speed to first use matters and the work happens one document at a time.
Time to value. A Word add-in is a web application that Office loads through a manifest, and Microsoft's Office Add-ins documentation describes both individual installation and centralized deployment by an administrator. In practice that means a lawyer can be using the tool on a live matter in days, not after a data-loading project.
Drafting, not just reviewing. Spellbook is built to generate and revise language as you write, from a blank page, a template or a precedent. If a large share of your week is producing first drafts rather than reviewing the other side's paper, a drafting-first tool fits the work more closely.
Scale that matches small teams. Spellbook says its cost is determined by the number of team members on a licence, and it offers a 7-day free trial. Both facts lower the barrier for a small firm or a lean in-house team to test it on real agreements before committing.
No estate required. Nothing about the core workflow depends on having a large archive. The value shows up on the first contract you open.
The trade-off runs the other way. If you need portfolio analysis across thousands of signed agreements, you will be stretching a drafting assistant past its design.
What does each reportedly cost?
Neither vendor publishes a price, and our directory records both as "Pricing on request." Here is what can and cannot be said.
Luminance is, on the vendor's own marketplace listing, a private offer sold on a 36-month term and sized by document volume rather than by seat. That is why we do not give a figure. Third-party pages do give figures, and they disagree with each other: one comparison page claims roughly $100,000 a year, another claims $2,000 or more per user per month, and an aggregator profile shows a per-user starting price that cannot be reconciled with a volume-based multi-year contract. None cites a primary source. Treat all of them as unverified. Our Luminance pricing breakdown traces each claim back as far as it goes.
Spellbook prices by team size and publishes no rate card. Third-party estimates for a seat range across more than an order of magnitude, from around twenty dollars to several hundred a month, and many of them are repeated from one another or published by competing vendors. Our Spellbook pricing breakdown lays out each reported figure and who published it.
What you can rely on is structure, not numbers:
| Luminance | Spellbook | |
|---|---|---|
| Priced on | Document volume, modules, term | Number of team members |
| Term | Multi-year private offers (36-month option on its marketplace listing) | Not published; quoted on the call |
| Free way in | None advertised | 7-day free trial |
| Budget before a sales call | No | Not really, but a trial lets you test first |
| What drives the total | How many documents and which modules | How many seats |
The practical consequence is about sequencing. Luminance has to enter your process early because the quote takes time and involves more people. Spellbook can be tested in a week, and that test tells you more than any estimate will.
Whichever you pursue, ask for the quote broken out by line, ask what is included in implementation, and ask for a shorter term alongside the longer one. The gap between them is what the commitment is worth to the vendor.
How do they compare with a lighter tool that publishes a price?
If neither quote-gated option looks right, the contract review category has tools that publish what they cost. Our directory shows two worth knowing:
- Gavel: Gavel Exec has a free tier of 25 queries and a paid tier at $160 per user per month. It was acquired by Relativity in June 2026 and continues to operate. Our Spellbook vs Gavel comparison covers the Word redlining side in detail.
- Genie AI: a free plan, Pro at $75 a month, and Enterprise from $600 a month, with a large open template library. See our Genie AI review.
A published price does not make a tool better. It makes it testable before a salesperson is involved, which for a small team is often the most valuable property of all. For the wider map of options, see our guide to AI contract review software, and for how rare published prices are across the whole market, the legal AI pricing guide.
Which team should choose which?
Work through the questions in order. The first answer that applies decides it.
1. Do you review or manage hundreds of contracts a month,
or need to search and analyze a large signed archive?
YES -> go to 2.
NO -> go to 4.
2. Do you have procurement, security review and budget
for a multi-year enterprise agreement?
YES -> Luminance. Request a scoped quote and a pilot.
NO -> go to 3.
3. Is the volume mostly inbound review in Word?
YES -> Spellbook, or a published-price tool such as Gavel,
on a short term. Revisit a platform when volume grows.
NO -> Fix the repository problem first, then reassess.
4. Do you draft or redline in Word as the main workflow?
YES -> go to 5.
NO -> A contract repository or document automation tool
may fit better than either of these.
5. Do you need a price you can see before talking to sales,
or are you a team of a few people?
YES -> Gavel (free tier) or Genie AI (free plan) first.
NO -> Spellbook. Use the free trial on your own paper.
Three rules apply whichever branch you land on. Test on your own agreements, not the vendor's sample, because model quality on a clean NDA says little about the lease or licence you actually negotiate. Ask where your documents are stored, who can see them, and whether they are used to train models. And name one person who owns adoption, because tools in this category fail on rollout far more often than on capability.
If you want to line up every option side by side, the full bench is at /categories/contract-review. Listings are free, featured placement is labelled, and neither affects ranking.
One piece of company context for the platform side of the decision: Luminance announced a $75 million Series C led by Point72 Private Investments in February 2025, reported by Legal IT Insider, with the company citing more than 700 customers across 70-plus countries at that time. Vendor funding is not a buying criterion on its own, but a multi-year agreement is the kind of commitment where it is reasonable to ask who owns the company and how it is financed.
Frequently asked questions
Is Luminance better than Spellbook for in-house teams?
It depends on volume and structure, not on which product is better in the abstract. An in-house team with a steady flow of inbound contracts, a large archive and a procurement process behind it gets more from Luminance's platform. A small in-house team that mostly drafts and redlines in Word, and wants to start on a seat-based plan with a trial, will usually find Spellbook the faster route. Both list in-house teams and law firms as their audience in our directory.
Does Luminance work in Microsoft Word?
Yes. Luminance's own documentation describes a Word add-in within its Negotiate module that generates first-pass redlines, applies playbooks, and guides review with checklists. This is a change from older descriptions of Luminance as a purely browser-based platform. What differs from Spellbook is not whether Word is supported but how central it is: Spellbook is built around the editing surface, while Luminance treats Word as one entry point into a wider platform.
Which is cheaper, Luminance or Spellbook?
Neither publishes a price, so a verified answer does not exist. Structurally, Spellbook is sold by team size and offers a 7-day free trial, which generally points to a lower entry cost and a lower commitment. Luminance is sold as a volume-based private offer on a multi-year term, which points to a larger commitment. Only a quote scoped to your own numbers settles it.
What do the two cost compared with Gavel?
Gavel is the one with a published number. Our directory records Gavel Exec as a free tier of 25 queries and a paid tier at $160 per user per month, while Luminance and Spellbook are both recorded as pricing on request. For a small team, that means Gavel can be evaluated and budgeted without a sales call, while the other two cannot. Gavel's ownership changed in June 2026 when Relativity acquired it, which is worth weighing alongside price.