Rillet has opened a central London office with founding hires across sales, deployment and support already on the ground, the company said.
The move follows UK and European customers driving 15% of net new ARR as of November 2026, Rillet said. International net new ARR more than tripled month over month, and the company now counts nearly 1,000 customers across 75 countries, including Black Forest Labs and Temporal. The expansion comes less than three months after Rillet raised a $100 million Series C at a $1 billion valuation led by ICONIQ with Sequoia and Andreessen Horowitz participating, according to the company.
For UK controllers, the change is practical. Instead of buying and implementing from across the Atlantic, they get a local team to evaluate the system, lead the deployment and answer support tickets after go-live.
Dave Arkell, CFO at Black Forest Labs, said his team chose Rillet to match its push to test what was possible. He said the finance stack needed AI in the architecture, with MCP connectivity and reliable data the team can act on and interact with. Black Forest Labs makes AI image models and built the FLUX 3 base used in fal Research's FLUX 3 Max text and image to video model, per fal's model listing.
Rillet has not disclosed a UK headcount target or go-live timelines.
Nicolas Kopp, CEO and co-founder of Rillet, said UK finance teams were already running on Rillet within a year of the US launch with almost no marketing and no local team. Rillet said LinkedIn named it to its 2026 Top Startups list of 50 U.S. companies, and said founding UK hires are signed but gave no numbers.
Rillet said its alliance with EY, strategic alliance with RSM and work with more than half of the Accounting Today top 20 CPA firms give it audit relationships to build on across EMEA. If the London team cannot cut evaluation time and days to close, the office is only a postcode.
