LLuminance

Luminance counts more than 700 organizations in over 70 countries as customers and says a quarter of the world’s largest law firms are among them. The London company, founded in 2015 by Cambridge mathematicians, raised a $75 million Series C in February 2025 and has since pushed into AI agents that do more than suggest edits: Agent Lumi marks up and routes contracts for approval, and Lumi Go negotiates drafts with counterparties on a customer’s behalf.

Luminance is best for law firms with large review and diligence workloads and for legal teams that handle a steady stream of routine contracts. Pricing is shared through sales without a public trial, and large law firm licenses are reported to run to hundreds of thousands of dollars a year. We rate it 7.6/10 on our scale. We have not used Luminance; this review is based on Luminance’s published information and third-party research.

Funding Rounds and Research on Luminance’s Scale

Luminance has a longer record than most legal AI vendors, and its funding announcements and third-party research give a clear picture of its scale.

The numbers show two businesses under one brand. Law firms were Luminance’s first market, through due diligence review, and they still bring large contracts such as Clyde and Co’s. The fastest growth, though, is on the corporate side, where customer numbers rose fivefold in two years. The agent launches follow that money: Agent Lumi is described for business users, sales, commercial and legal teams.

For a law firm buyer, that means two things. The review platform is mature and well tested in diligence work. The newest agent features are designed around in-house contract flows, so a firm should check how they apply to client matters before paying for them.

A Review Platform, Word Add-In and Legal Model Agents

Luminance combines a document review platform, a Microsoft Word add-in and a set of agents built on its own legal model. The model, which Luminance says has been exposed to more than 150 million verified legal documents, sits behind what the company calls a Panel of Judges: a mixture-of-experts approach that uses probabilistic consensus for contract generation, negotiation and post-execution analysis.

Due Diligence and Document Review

The core platform reviews large document sets, clusters similar documents and flags outliers. This is the work that brought Luminance into law firms and, according to Sacra, into all of the Big Four by 2021. Lawyers use it to find unusual clauses across a data room instead of reading every contract in sequence.

Contract Markup in Word

A Microsoft Word integration marks up contracts against a set of standards, so a lawyer sees suggested changes in the document they already have open.

Agent Lumi

Agent Lumi combines the legal model with tools and memory. It accepts requests about contracts in any language. Luminance’s NDA example runs end to end:

1. An incoming NDA arrives and the user asks Agent Lumi to handle it.
2. The agent marks it up to the company’s standards.
3. It triggers whatever approvals the rules require.
4. It summarizes the changes for the user.
5. It generates a new version to send to the counterparty.

Agent Lumi also produces recurring reports, such as customers with upcoming termination dates, and flags inefficiencies, such as a clause that keeps getting negotiated, so the legal team can update its templates. Short-term and long-term memory let it tailor responses to each user, and users can see and refine every reasoning step.

Lumi Go

Lumi Go handles the back-and-forth of negotiation. Drafts sent to counterparties can be negotiated by the AI on the customer’s behalf, which makes it one of the few legal tools that acts outside the firm rather than only advising lawyers inside it.

Built With a Law Firm Partner

Luminance has close ties to private practice. Slaughter and May was an early design partner according to Sacra, and it invested again in the 2025 Series C. That history shows in the review platform, which was shaped around how firms run due diligence, and it gives law firm buyers a reference point when they ask how the tools hold up on real client matters.

Playbooks, Escalations and Limits on Lumi Go

Lawyers set the standards and playbooks the agents follow, approve escalations and own any advice to clients. Negotiation by Lumi Go needs firm limits on what the AI may concede and when it must stop and ask. Complex, bespoke deals remain lawyer work.

Contact-the-Vendor Pricing and No Free Trial

Luminance does not publish prices, and its Capterra listing asks buyers to contact the vendor and shows no free trial. Sacra’s research describes how deals are structured.

Spreading an Assumed License Across a Firm

Exact figures need a quote. These illustrations apply round, assumed license values within the reported range to show how the cost spreads across a firm; they are not Luminance prices.

• A 100-lawyer firm on an assumed $200,000 annual license: that is $2,000 per lawyer a year, or about $167 a month.
• A 400-lawyer firm on an assumed $500,000 license: $1,250 per lawyer a year, or about $104 a month.
• A single diligence project: under usage-based terms the cost tracks document volume, so a large data room costs more than a small one; ask for the per-document or per-matter rate in writing.

Questions for the sales process: whether agent features such as Lumi Go cost extra, how usage fees are measured, whether fees can pass through to clients on matters, and what renewal increases look like on multi-year terms.

Luminance Compared With Harvey, Legora, Spellbook and CoCounsel Legal

Legal AI tools for law firms divide into broad AI workspaces, drafting assistants inside Word and research-led tools tied to legal content. Luminance sits closest to contract review and negotiation.

Harvey and Legora are the broad choices for firms that want one AI workspace. Spellbook is lighter and lives in Word. CoCounsel fits research-heavy practices. Luminance leads on diligence review at volume and for Lumi Go’s direct negotiation with counterparties. See more in our guides to AI agents for law firms and AI agents for legal teams.

Large Firms With Heavy Diligence Loads

• Firms with heavy diligence work: clustering and outlier detection across large document sets is Luminance’s longest-standing strength.
• Large firms with enterprise budgets: the reported license sizes fit firms that already buy legal tech at that level.
• Legal teams with routine contract volume: Agent Lumi’s NDA workflow shows the kind of repeatable work it is designed to take on.
• Firms advising clients on contract operations: Lumi Go’s negotiation and Agent Lumi’s reports suit firms running managed contract services.
• Multinational practices: Agent Lumi accepts requests in any language, and Luminance has customers in more than 70 countries.

Small Firms and Research-Led Practices

• Solo lawyers and small firms on a budget: there is no self-serve plan or trial.
• Research-led practices: a tool tied to case law content, such as CoCounsel Legal or Lexis+ AI, fits better.
• Firms that need peer reviews before buying: Luminance has no user reviews on Capterra yet.
• Firms that want a broad AI workspace: Harvey or Legora cover research, drafting and review in one place.
• Teams uneasy about AI acting externally: Lumi Go negotiates directly with counterparties, which some firms will not allow on client matters.

Corporate-Focused Agents and Negotiation Limits

• Agent features aimed at corporate teams: Agent Lumi is described for business and in-house users. Confirm what applies to a law firm’s client work.
• Negotiation limits: letting an AI negotiate with the other side needs clear fallback positions, escalation rules and client consent where required.
• Cost: reported enterprise licenses run to hundreds of thousands of dollars a year, and multi-year deals carry that forward.
• Security documentation: Luminance’s launch materials do not yet set out certifications, so request its security pack and data handling terms before uploading client documents.
• Vendor figures: customer counts and growth rates come from Luminance, and the revenue figures are Sacra estimates.
• Memory and data use: Agent Lumi learns from each user’s past interactions, so ask how that memory is stored, who can see it and whether it stays separate between clients.

A $75 Million Series C Led by Point72

• On February 18, 2025, Luminance announced a $75 million Series C led by Point72 Private Investments, bringing the amount raised in 12 months to more than $115 million and funding new offices in San Francisco, Dallas and Toronto.
• The same day, Sifted reported that Luminance had begun rolling out AI agents, one that completes tasks on contracts and one that drafts and negotiates them, after testing that started in late 2024.

Large Diligence Practices Get Luminance’s Best Work

For large law firms with heavy diligence and contract review work, Luminance is worth a demo. It scores 7.6/10 on our scale: strong on autonomy thanks to agents that mark up, route and negotiate contracts, with room to grow through published pricing, more documented integrations, public user ratings and fuller security detail. A decade of legal AI work, more than 700 customers and a quarter of the world’s largest firms on its list make it a credible vendor.

The fit question is direction. Luminance’s growth and newest agents point toward corporate legal teams. Law firms should test the review platform on a real data room, ask for law firm references and decide in advance whether they will let Lumi Go negotiate on client matters.

Negotiating Alone and the Panel of Judges

How Much Does Luminance Cost?

Luminance does not publish prices. Sacra reports that large law firms sign enterprise licenses that can reach hundreds of thousands of dollars a year, while smaller firms and specific projects pay usage-based fees tied to document volume or matters.

Can Luminance Negotiate Contracts on Its Own?

Yes. Lumi Go can negotiate drafts with counterparties on the customer’s behalf, and Agent Lumi can mark up an NDA, trigger approvals and produce the next version. Firms set the standards it follows.

What Is the Luminance Panel of Judges?

It is Luminance’s mixture-of-experts approach, which uses probabilistic consensus across models for contract generation, negotiation and post-execution analysis. It sits on a legal model exposed to more than 150 million verified legal documents.

How Does Luminance Compare With Harvey?

Harvey is a broad legal AI workspace used across practice areas. Luminance is more focused on contract review, due diligence and negotiation, including direct negotiation with counterparties through Lumi Go. Neither publishes prices.

Does Luminance Offer a Free Trial?

No. Its Capterra listing shows no free trial and asks buyers to contact the vendor, so evaluation runs through a demo and sales process.