Rillet, the U.S. accounting software startup that reached a $1 billion valuation this summer, has opened an office in London, marking its formal entry into the United Kingdom.
The expansion, announced on November 9, comes roughly three months after the company closed a $100 million Series C round in August. That raise lifted its total funding to more than $200 million, according to a report by Korea IT Times.
With fresh capital and a growing international customer list, Rillet is positioning itself as an AI-native alternative to the enterprise resource planning systems that have dominated corporate finance for decades.
Funding Fuels an International Push
The August Series C gave Rillet unicorn status and the resources to look beyond its home market. The London move is one of the first visible uses of that capital outside the United States.
The company says its customer count has climbed to nearly 1,000 across 75 countries, up from more than 600 when the funding was announced. Rillet also reported that its international net new annual recurring revenue more than tripled month over month.
Following Customers Who Arrived First
Rillet said British companies began using its platform before it had any local presence, which created demand for support in the region. The new office will handle sales, implementation and customer service, and the company plans to keep hiring.
Founder and CEO Nicolas Kopp noted that within a year of the U.S. launch, "we already had finance teams in the UK running on Rillet."
European customers named by the company include Black Forest Labs, Temporal and Primer. Dave Arkell, CFO of Black Forest Labs, said his team chose Rillet because it wanted AI built into the core of its financial systems rather than bolted on as a separate feature.
How the Platform Differs From Legacy ERP
SAP, Oracle and NetSuite have long provided the software businesses rely on for transactions, reporting and accounting controls. Rillet is betting that a system designed around AI from the start can compete with these entrenched players.
Its product combines a real-time general ledger, continuous close capabilities and AI agents in a single platform. The agents operate under the same accounting policies and controls that apply to human staff, rather than running in separate automation tools.
Because the general ledger underpins reporting, reconciliation and audits, placing AI there could cut manual work and speed up reporting. It also raises the stakes for accuracy, permissions and auditability. Rillet says human approval remains in place and that AI-assisted actions are logged in an audit trail.
The Hurdles of Replacing Core Systems
Switching accounting systems is a major undertaking. Companies must migrate records, revalidate internal controls, connect existing applications and keep reporting accurate throughout the transition.
Those challenges can be sharper in Europe, where businesses deal with varied tax regimes, accounting practices and regulators. Rillet's relationships with firms such as EY and RSM may help it navigate implementation in enterprise accounts.
The company has not released independently verified data showing how much its software reduces accounting costs or closing times across its customers.
A Broader Contest Over AI in Enterprise Software
Rillet's expansion highlights an open question in the sector: whether AI will mainly strengthen existing ERP platforms or speed adoption of products built for AI from day one.
Incumbents bring deep customer relationships, mature compliance tools and wide integration ecosystems. Challengers like Rillet are competing on automation, quicker implementation and tighter workflows.
What It Means for Founders and Finance Teams
For founders, Rillet's trajectory shows how a well-funded startup can follow organic international demand rather than forcing entry into new markets. Customers arriving before a local office existed gave the company a ready foothold in the UK.
For the wider industry, the real test will come from measurable results. Whether AI-native accounting platforms can displace established systems will depend on proven reliability, enterprise-scale deployments, customer retention and the ability to meet compliance requirements in each market they enter.
Source: Korea IT Times
