'Facts are our currency': Meet the legal tech founder helping lawyers find the facts
Gregory Mostyn, founder of legal tech company Wexler, on building a fact intelligence platform for litigators.
Contents
Gregory Mostyn grew up in a family of lawyers - his father is a former High Court judge, his brother is a partner at a major firm, and his stepmother is a barrister.
Despite that background, he once imagined a very different career as an actor. While he had “five lines” on the popular HBO and BBC banking drama Industry, playing a posh student, he ultimately decided acting was not for him.
Someone once asked him if he would be happy “sitting in a one-bed flat eating baked beans cold because you can’t afford electricity, but you love it because you’re an actor”. “At that point,” he says, “I thought maybe I’d take a different path.”
Instead, he found himself returning to the legal world “in a roundabout way”, not as a lawyer but as the founder of Wexler, a London-based legal tech company building a fact intelligence platform for litigation teams.
Founded in 2023 alongside Kush Madlani, the company focuses on helping disputes lawyers extract facts, build chronologies and test case theories from vast datasets of evidence.
The startup recently raised a $5.3 million seed round led by Pear VC with investments from Seedcamp, The LegalTech Fund and Myriad Venture Partners, and counts firms such as Clifford Chance, Goodwin and HSF Kramer among its customers.
I sat down with Mostyn to hear about how it’s going so far.
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How it started
Wexler’s London office sits next to the Royal Courts of Justice, a fitting base for a company built around litigation. For Mostyn, though, the connection to the courts runs deeper than proximity.
In a family full of lawyers, healthy legal debate filled the dinner table growing up. One familiar childhood memory stuck with him. “I remember my dad with 10 ring binders full of data to review each night before he was in court the next day,” he says.
That image of lawyers buried in paper and wrestling with facts would eventually become the seed of Wexler.
The company came out of his time at startup accelerator Entrepreneur First, where he met his co-founder Madlani, a former JPMorgan derivatives trader who later completed a master’s in machine learning and, as Mostyn puts it, “was training models before LLMs were a thing”.
We took the early bet that long-term, being focused and being a scalpel...would pay off.
Together, they saw an opportunity in legal AI. “At the time, legal AI was basically Harvey,” Mostyn says. “They were trying to do every legal task.”
“We don’t try to boil the ocean,” he says. “We took the early bet that long-term, being focused and being a scalpel and going really deep into specific workflows would pay off.”
Their target was litigators: the subset of lawyers who are, in his words, “very exacting and demanding in their standards”.
“Facts are our currency,” he says. “Fact intelligence is the sort of category that we’ve created.”
Millions of documents
The scale of litigation data is enormous, with individual cases often involving hundreds of thousands of documents. Wexler’s platform can currently analyse around 500,000 documents per upload, including multilingual datasets, with new funding set to expand that capacity to one million documents per upload.
Things are buried in WhatsApp messages, email chains or cell B14 of a spreadsheet.
“Litigation is extremely, extremely messy,” he says. “You’re dealing with hundreds of thousands or even millions of documents. Things are buried in WhatsApp messages, email chains or cell B14 of a spreadsheet. Context shifts, time zones change, languages change.”
In many cases, the challenge lies in the nuance of what was said and when. “Someone says something in a deposition, then you find they said something completely different 20 years ago.”
Grounded in facts
Generic large language models like ChatGPT or Claude Cowork can struggle in that environment and “get things wrong”, he says. “That kind of inaccuracy is not something you can have in a high-stakes investigation.”
Wexler’s solution is architectural. Rather than asking one model to perform multiple reasoning steps at once, the system “daisy chains together all these different models”.
“We don’t ask one model to do too much in one go,” he explains. “Instead of going A to Z in one step, we go A to B, then B to C.”
The aim is to reduce variance and hallucination with every output grounded in fact.
“Every single assertion is grounded in the documents and referenced back to the sentence that it’s taken from. We show you exactly where it’s from, down to the word,” he says.
“One click, and you can jump into the document and verify.”
Law Firm | Trainee First Year | Trainee Second Year | Newly Qualified (NQ) |
|---|---|---|---|
| Addleshaw Goddard | £52,000 | £56,000 | £100,000 |
| Akin | £60,000 | £65,000 | £174,418 |
| A&O Shearman | £56,000 | £61,000 | £150,000 |
| Ashurst | £57,000 | £62,000 | £140,000 |
| Baker McKenzie | £56,000 | £61,000 | £145,000 |
| Bird & Bird | £48,500 | £53,500 | £102,000 |
| Bristows | £48,000 | £52,000 | £95,000 |
| Bryan Cave Leighton Paisner | £55,000 | £58,000 | £125,000 |
| Burges Salmon | £49,500 | £51,500 | £76,000 |
| Charles Russell Speechlys | £52,000 | £55,000 | £93,000 |
| Cleary Gottlieb | £62,500 | £67,500 | £164,500 |
| Clifford Chance | £56,000 | £61,000 | £150,000 |
| Clyde & Co | £48,500 | £51,000 | £85,000 |
| CMS | £50,000 | £55,000 | £120,000 |
| Cooley | £55,000 | £60,000 | £157,000 |
| Davis Polk | £65,000 | £70,000 | £180,000 |
| Debevoise | £55,000 | £60,000 | £173,000 |
| Dechert | £55,000 | £61,000 | £165,000 |
| Dentons | £52,000 | £56,000 | £104,000 |
| DLA Piper | £52,000 | £57,000 | £130,000 |
| Eversheds Sutherland | £50,000 | £55,000 | £110,000 |
| Farrer & Co | £47,000 | £49,000 | £88,000 |
| Fieldfisher | £48,500 | £52,000 | £100,000 |
| Freshfields | £56,000 | £61,000 | £150,000 |
| Fried Frank | £55,000 | £60,000 | £175,000 |
| Gibson Dunn | £60,000 | £65,000 | £180,000 |
| Goodwin Procter | £55,000 | £60,000 | £175,000 |
| Gowling WLG | £48,500 | £53,500 | £105,000 |
| Herbert Smith Freehills Kramer | £56,000 | £61,000 | £145,000 |
| HFW | £50,000 | £54,000 | £103,500 |
| Hill Dickinson | £43,000 | £45,000 | £80,000 |
| Hogan Lovells | £56,000 | £61,000 | £140,000 |
| Irwin Mitchell | £43,500 | £45,500 | £78,000 |
| Jones Day | £60,000 | £68,000 | £165,000 |
| K&L Gates | £50,000 | £55,000 | £115,000 |
| Kennedys | £43,000 | £46,000 | £85,000 |
| King & Spalding | £62,000 | £67,000 | £175,000 |
| Kirkland & Ellis | £60,000 | £65,000 | £174,418 |
| Latham & Watkins | £60,000 | £65,000 | £174,418 |
| Linklaters | £56,000 | £61,000 | £150,000 |
| Macfarlanes | £56,000 | £61,000 | £140,000 |
| Mayer Brown | £55,000 | £60,000 | £150,000 |
| McDermott Will & Schulte | £65,000 | £70,000 | £174,418 |
| Milbank | £65,000 | £70,000 | £174,418 |
| Mills & Reeve | £45,000 | £47,000 | £84,000 |
| Mischon de Reya | £50,000 | £55,000 | £100,000 |
| Norton Rose Fulbright | £56,000 | £61,000 | £135,000 |
| Orrick | £60,000 | £65,000 | £160,000 |
| Osborne Clarke | £55,500 | £57,500 | £97,000 |
| Paul Hastings | £60,000 | £68,000 | £173,000 |
| Paul Weiss | £60,000 | £65,000 | £180,000 |
| Penningtons Manches Cooper | £48,000 | £50,000 | £83,000 |
| Pinsent Masons | £52,000 | £57,000 | £105,000 |
| Quinn Emanuel | n/a | n/a | £180,000 |
| Reed Smith | £53,000 | £58,000 | £125,000 |
| Ropes & Gray | £60,000 | £65,000 | £165,000 |
| RPC | £48,000 | £52,000 | £95,000 |
| Shoosmiths | £45,000 | £47,000 | £105,000 |
| Sidley Austin | £60,000 | £65,000 | £175,000 |
| Simmons & Simmons | £54,000 | £59,000 | £120,000 |
| Simpson Thacher | n/a | n/a | £178,000 |
| Skadden | £58,000 | £63,000 | £177,000 |
| Slaughter and May | £56,000 | £61,000 | £150,000 |
| Squire Patton Boggs | £50,000 | £55,000 | £110,000 |
| Stephenson Harwood | £50,000 | £55,000 | £105,000 |
| Sullivan & Cromwell | £65,000 | £70,000 | £174,418 |
| Taylor Wessing | £52,000 | £57,000 | £115,000 |
| TLT | £44,000 | £47,500 | £85,000 |
| Travers Smith | £55,000 | £60,000 | £130,000 |
| Trowers & Hamlins | £47,000 | £51,000 | £85,000 |
| Vinson & Elkins | £60,000 | £65,000 | £173,077 |
| Watson Farley & Williams | £51,500 | £56,000 | £107,000 |
| Weightmans | £36,000 | £38,000 | £70,000 |
| Weil | £60,000 | £65,000 | £170,000 |
| White & Case | £62,000 | £67,000 | £175,000 |
| Willkie Farr & Gallagher | £60,000 | £65,000 | £170,000 |
| Withers | £47,000 | £52,000 | £95,000 |
| Womble Bond Dickinson | £43,000 | £45,000 | £83,000 |
Rank | Law Firm | Revenue | Profit per Equity Partner (PEP) |
|---|---|---|---|
| 1 | DLA Piper* | £3,130,000,000 | £2,500,000 |
| 2 | A&O Shearman | £2,900,000,000 | £2,000,000 |
| 3 | Clifford Chance | £2,400,000,000 | £2,100,000 |
| 4 | Hogan Lovells | £2,320,000,000 | £2,400,000 |
| 5 | Linklaters | £2,320,000,000 | £2,200,000 |
| 6 | Freshfields | £2,250,000,000 | Not disclosed |
| 7 | CMS** | £1,800,000,000 | Not disclosed |
| 8 | Norton Rose Fulbright* | £1,800,000,000 | Not disclosed |
| 9 | HSF Kramer | £1,360,000,000 | £1,400,000 |
| 10 | Ashurst | £1,030,000,000 | £1,390,000 |
| 11 | Clyde & Co | £854,000,000 | Not disclosed |
| 12 | Eversheds Sutherland | £769,000,000 | £1,400,000 |
| 13 | Pinsent Masons | £680,000,000 | £790,000 |
| 14 | Slaughter and May*** | £650,000,000 | Not disclosed |
| 15 | BCLP* | £640,000,000 | £790,000 |
| 16 | Simmons & Simmons | £615,000,000 | £1,120,000 |
| 17 | Bird & Bird** | £580,000,000 | £720,000 |
| 18 | Addleshaw Goddard | £550,000,000 | £1,000,000 |
| 19 | Taylor Wessing | £526,000,000 | £1,100,000 |
| 20 | Osborne Clarke** | £476,000,000 | £800,000 |
| 21 | DWF | £466,000,000 | Not disclosed |
| 22 | Womble Bond Dickinson | £450,000,000 | Not disclosed |
| 23 | Kennedys | £428,000,000 | Not disclosed |
| 24 | Fieldfisher | £385,000,000 | £1,000,000 |
| 25 | Macfarlanes | £371,000,000 | £3,100,000 |
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Beyond busywork
The time savings can be significant, sometimes more than 75% for some tasks he says, but time saved is only part of the story.
“A real benefit is finding that piece of information you wouldn’t have otherwise found - that smoking gun - that critical fact that could be the difference between winning and losing the case,” he says.
A real benefit is finding that piece of information you wouldn’t have otherwise found.
Those efficiency gains inevitably raise questions about how tools like Wexler might reshape traditional billing models, though Mostyn is cautious. “I don’t think the much-heralded death of the billable hour is quite there yet.”
Most of his clients, he says, are not short of work. Instead, they are looking to “reduce the busy work and focus on higher-value strategic work”.
Growing globally
A significant share of Wexler’s users are in the US and continued expansion across the Atlantic is a priority with “some boots on the ground in the US imminently,” he says.
The “universal” platform works globally because “facts have no frontier,” he says. “It’s the same facts in the UK as in the US, as in Australia, as in continental Europe. The law changes, but the facts don’t.”
It’s the same facts in the UK as in the US, as in Australia, as in continental Europe.
The team is currently 15, with two to three hires joining each month. Advances in AI have made it possible for startups to grow quickly without building the large teams traditionally required to scale.
“The amazing thing with AI now is that you can be lean,” he says. “You don’t have to hire hundreds of staff anymore.”
Despite growing quickly, Mostyn says the company is “nearly profitable”. While there may be additional fundraising in the future, he says the company is currently funding much of its growth through revenue.
Office culture
The company operates a largely in-office culture in London, which Mostyn describes as “critical at this stage”. It shortens feedback loops between product and sales and allows for frequent discussions about what to build, customer feedback and ideas.
The job demands frequent US travel and late-night calls, but Mostyn rejects the glorification of extreme startup culture.
“My most precious resource is my team,” he says. “I want my team to be energised, to be refreshed.”
“Yes, they work extremely hard, but having a life outside work is one of our company’s values.”
Outside the office, Mostyn is an “improving” golf player and a self-described “long-suffering supporter of Tottenham football club”. He also still has an IMDb page from his brief appearance in Industry season two where he is credited simply as “Posh Student”.
| Firm | London office since | Known for in London |
|---|---|---|
| Akin | 1997 | Restructuring, funds |
| Baker McKenzie | 1961 | Finance, capital markets, TMT |
| Davis Polk | 1972 | Leveraged finance, corporate/M&A |
| Gibson Dunn | 1979 | Private equity, arbitration, energy, resources and infrastructure |
| Goodwin | 2008 | Private equity, funds, life sciences |
| Kirkland & Ellis | 1994 | Private equity, funds, restructuring |
| Latham & Watkins | 1990 | Finance, private equity, capital markets |
| McDermott Will & Schulte | 1998 | Finance, funds, healthcare |
| Milbank | 1979 | Finance, capital markets, energy, resources and infrastructure |
| Paul Hastings | 1997 | Leveraged finance, structured finance, infrastructure |
| Paul Weiss | 2001 | Private equity, leveraged finance |
| Quinn Emanuel | 2008 | Litigation |
| Sidley Austin | 1974 | Leveraged finance, capital markets, corporate/M&A |
| Simpson Thacher | 1978 | Leveraged finance, private equity, funds |
| Skadden | 1988 | Finance, corporate/M&A, arbitration |
| Sullivan & Cromwell | 1972 | Corporate/M&A, restructuring, capital markets |
| Weil | 1996 | Restructuring, private equity, leverage finance |
| White & Case | 1971 | Capital markets, arbitration, energy, resources and infrastructure |
| Law firm | Type | First-year salary |
|---|---|---|
| White & Case | US firm | £32,000 |
| Stephenson Harwood | International | £30,000 |
| A&O Shearman | Magic Circle | £28,000 |
| Charles Russell Speechlys | International | £28,000 |
| Freshfields | Magic Circle | £28,000 |
| Herbert Smith Freehills | Silver Circle | £28,000 |
| Hogan Lovells | International | £28,000 |
| Linklaters | Magic Circle | £28,000 |
| Mishcon de Reya | International | £28,000 |
| Norton Rose Fulbright | International | £28,000 |
Law Firm | Trainee First Year | Trainee Second Year | Newly Qualified (NQ) |
|---|---|---|---|
| A&O Shearman | £56,000 | £61,000 | £150,000 |
| Clifford Chance | £56,000 | £61,000 | £150,000 |
| Freshfields Bruckhaus Deringer | £56,000 | £61,000 | £150,000 |
| Linklaters | £56,000 | £61,000 | £150,000 |
| Slaughter and May | £56,000 | £61,000 | £150,000 |
Law Firm | Trainee First Year | Trainee Second Year | Newly Qualified (NQ) |
|---|---|---|---|
| A&O Shearman | £56,000 | £61,000 | £150,000 |
| Clifford Chance | £56,000 | £61,000 | £150,000 |
| Freshfields Bruckhaus Deringer | £56,000 | £61,000 | £150,000 |
| Linklaters | £56,000 | £61,000 | £150,000 |
| Slaughter and May | £56,000 | £61,000 | £150,000 |
Law Firm | Trainee First Year | Trainee Second Year | Newly Qualified (NQ) |
|---|---|---|---|
| Ashurst | £57,000 | £62,000 | £140,000 |
| Bryan Cave Leighton Paisner | £55,000 | £58,000 | £125,000 |
| Herbert Smith Freehills | £56,000 | £61,000 | £145,000 |
| Macfarlanes | £56,000 | £61,000 | £140,000 |
| Travers Smith | £55,000 | £60,000 | £130,000 |
| Firm | Merger year | Known for in London |
|---|---|---|
| BCLP | 2018 | Real estate, corporate/M&A, litigation |
| DLA Piper | 2005 | Corporate/M&A, real estate, energy, resources and infrastructure |
| Eversheds Sutherland | 2017 | Corporate/M&A, finance |
| Hogan Lovells | 2011 | Litigation, regulation, finance |
| Mayer Brown | 2002 | Finance, capital markets, real estate |
| Norton Rose Fulbright | 2013 | Energy, resources and infrastructure, insurance, finance |
| Reed Smith | 2007 | Shipping, finance, TMT |
| Squire Patton Boggs | 2011 | Corporate/M&A, pensions, TMT |
Law Firm | Trainee First Year | Trainee Second Year | Newly Qualified (NQ) |
|---|---|---|---|
| Ashurst | £57,000 | £62,000 | £140,000 |
| Bryan Cave Leighton Paisner | £55,000 | £58,000 | £125,000 |
| Herbert Smith Freehills Kramer | £56,000 | £61,000 | £145,000 |
| Macfarlanes | £56,000 | £61,000 | £140,000 |
| Travers Smith | £55,000 | £60,000 | £130,000 |
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