Antidote’s $5m seed moves law-firm billing checks to the timesheet

On 21 January Antidote, a London-based company that checks law firms’ time entries against their clients’ billing rules, announced a $5m (£3.7m) seed round led by Lakestar. Concept Ventures, The LegalTech Fund and a group of industry angels also took part. The round follows a $2m pre-seed in 2025 and takes total funding to $7m, according to the company, which says the money will pay for product development and expansion in the US.

The business trades as Antidote Legal. The company behind it, Team34 Ltd, was incorporated at Companies House on 17 April 2024. Nicholas d’Adhemar is founder and chief executive. He previously founded and ran Apperio, a spend-management platform for corporate legal departments, which Persuit, an outside counsel management company, acquired in May 2025, as LawNext reported. Artificial Lawyer reports that d’Adhemar had left Apperio about 18 months before that sale. His co-founder, Matt Lyons, is Antidote’s CTO and was chief product and technology officer at Apperio; d’Adhemar told Artificial Lawyer the pair worked together there for seven years.

The rules Antidote checks are written by the clients. Large clients issue outside counsel guidelines (OCGs), rulebooks that set out how their law firms may record time and what an invoice may contain. Client-side compliance tools scan incoming bills for banned words, block billing and vague descriptions, then reject the lines that fail, Antidote wrote in a July 2025 post. The firm then rewrites the entries or writes them off. The company says non-compliance write-offs and rejected invoices cost firms 8–12% of billable hours a year. A partner at a large US firm whom d’Adhemar met during his early discovery work still has between a quarter and a third of his submitted invoices rejected, Artificial Lawyer reports.

Antidote moves that check earlier. Billing staff catch problems only after the work is logged, the keyword blockers built into timekeeping software do not rewrite entries, and firms still lean on manual end-of-month reviews, the company says. Antidote checks each entry when it is recorded. The seed round is a bet that firms will pay to apply their clients’ rules to themselves before the clients’ own software does it for them.

A check when the time is logged

The software sits on top of a firm’s existing time-recording and practice management systems. It reads every time entry, checks it against the client’s OCGs and the firm’s own standards, and suggests a compliant rewrite before a bill is sent, the company said. LawNext reports that lawyers can accept a suggested rewrite directly in an email without logging in to the platform, and that the product combines the written rules with each client’s historical payment patterns, so it reflects what clients actually pay for.

Antidote’s July 2025 post gives an example. The entry “Call with client, reviewed contract, internal meeting.” becomes “Consulted with client on contract terms; analyzed contract provisions for client deliverables.” The lawyer can accept, edit or override the suggestion.

“Law firm billing compliance is one of the biggest sources of revenue leakage inside firms, not to mention being a generally despised manual task that adds to client friction,” d’Adhemar said in the funding announcement. He told LawNext that Antidote was built after 2022, once large language models had arrived, and set it against incumbents adding AI to older systems.

From the client side to the firm side

Apperio served the buyers of legal work: in-house teams tracking what they spent on outside firms. Antidote sells to the firms on the other side of those invoices. Lakestar cites that history. Navid Meyer, venture partner at Lakestar, said d’Adhemar has “lived the problem as both a lawyer and a private equity client” and has already built and scaled legal spend management businesses.

d’Adhemar also says he did the customer work before the engineering. He told Artificial Lawyer he had the idea for some time and held discovery meetings with law firms before raising money or writing code. “There are infinite things you can build, but comparatively few that you should,” he said in that interview.

The company’s name for what it is selling against is the ‘Saturday morning problem’: a partner opening a laptop at the weekend to fix a pile of time entries for several clients, each with its own guidelines, none of that time billable. Its July 2025 post says one in three invoices is still rejected after that work.

What $7m has to prove

LawNext, drawing on figures from d’Adhemar, puts the revenue of the AmLaw 200, the 200 highest-grossing US law firms, at roughly $140bn (£104bn) in 2024, and notes that losing even 5% of that to billing compliance would mean $7bn a year.

Antidote says leading firms in the US, Australia and its home market already use the software, but it names none of them. LawNext points out that it is not the first legal product aimed at OCG compliance, and the timekeeping tools Antidote sits beside, which its own post names as Intapp Time and iTimekeep, already carry basic rules engines. The difference Antidote claims is the rewrite, delivered at the point of entry rather than at the pre-bill.

Antidote is spending the seed money on product development and the US. With $7m raised, two founders who have already built software for legal spend and no customer yet named on the record, its next milestone is a US firm saying publicly that its rejected invoices and write-offs fell.