The room where the invoice talks back
It is 4:14 p.m. on a Tuesday in the back-office of a mid-sized hospital system. An invoice arrives - paper once, now a PDF. Somewhere across the hospital, a department head needs to approve it. The vendor wants to know when they get paid. The CFO wants to know what bucket this lands in. The auditor will, eventually, want to know who said yes and why.
Ten years ago, this was a phone tree. Five years ago, an email chain. Today, increasingly, it is a Stampli screen, with the conversation living on the invoice itself and an AI named Billy filling in the boring parts. It is not the kind of story that gets you on the cover of a magazine - which is precisely why it is worth telling.
The most expensive boring problem in the building
Every company pays vendors. Most companies pay vendors badly. The average invoice still bounces between four to seven people before it clears a finance system, picking up emails, side messages, Post-it notes, and a layer of opinion no software has ever managed to capture.
The traditional response has been to digitize the form. Scan it, OCR it, push it into the ERP. The Feldman brothers - Eyal and Ofer - took one look at this approach and concluded, with a kind of brotherly bluntness, that everyone was solving the wrong problem. The bottleneck was never the data. The bottleneck was the conversation around the data.
Two brothers, one weird hypothesis
Eyal Feldman and his brother Ofer founded Stampli in 2015. Eyal runs the company. Ofer runs the engineering. Their hypothesis, then as now: keep every comment, approval, question, and AI suggestion stamped directly to the invoice, and you fix accounts payable. The name is on the wall - a stamp.
This was unfashionable advice in 2015. The cool money was on robotic process automation, the slightly-less-cool money was on standalone OCR vendors, and the safe money was on whatever Bill.com was doing. Stampli's bet sat in the awkward middle: a SaaS workspace that treated the invoice as the source of truth and stitched the messy human conversation back to it.
What they sold first
The earliest Stampli was less an AP platform and more a collaboration layer for AP teams - a way to put threaded comments and approvals on top of an invoice without making people leave the document. The AI came later. The collaboration came first. That ordering matters, and most competitors got it backwards.
Billy, the bot that learned accounts payable
Billy the Bot is the AI agent at the center of Stampli's pitch. The name is intentionally goofy. The training data is not. Billy has been trained on more than $150B in annual spend across more than 70 ERPs, and that scale is what separates Stampli's AI from a wrapper on a foundation model.
What Billy does, in plain English: codes invoices line-by-line by learning your accounting history; matches purchase orders, receipts, and invoices in real time (2- and 3-way matching); validates vendors; flags duplicates; routes approvals dynamically; and increasingly, handles procurement requests by turning free-text into structured POs. None of this is glamorous. All of it is exactly what mid-market finance teams want.
AP Automation
The core platform - capture, code, route, approve. The thing that started it all.
Billy the Bot
The AI agent that codes line items, runs PO matching, and catches duplicates before humans do.
Direct Pay
Built-in ACH, check, card, and international payments. Vendors get paid without leaving Stampli.
Stampli Card
Configurable corporate credit cards with spend controls and AP integration baked in.
Vendor Management
A self-service portal that handles onboarding, W-9s, and banking info without an email chain.
Procurement
Free-text purchase requests in, structured POs and approvals out. The pre-invoice half of the lifecycle.
A decade in receipts
Eyal and Ofer Feldman found Stampli. The original product is an invoice collaboration workspace.
First institutional funding from SignalFire and Bloomberg Beta. The company plants a flag in Mountain View.
$25M Series B. AP automation goes from "nice to have" to "the whole stack is moving online."
$50M Series C led by Insight Partners. Eyal makes the Top 50 SaaS CEOs list.
Stampli Direct Pay launches. Payments now live inside the AP platform.
$61M Series D led by Blackstone. Total raised crosses $145M.
Billy training data crosses $100B in annual spend. The AI label is no longer a marketing claim.
Brand refresh, expanded procurement product, ~1,600 customers, ~280 employees.
Numbers that justify the rent
The case for Stampli is not made on demo day. It is made in customer renewals, expansion deals, and the slow accumulation of integrations that lock the product into a finance team's nervous system. A few of those numbers, for the skeptical reader:
Funding by round
Stampli's customer list runs across healthcare systems, higher education, construction firms, retail chains, professional services, and manufacturing. The common thread is not industry. It is the shape of the problem: too many invoices, too many approvers, too many ERPs, and an AP team that has been promised software salvation roughly once a quarter for the last twenty years.
An honest sentence about the work
Stampli's mission statement, stripped of marketing varnish, is roughly this: keep the invoice at the center, keep humans in the loop, keep the AI honest. The company has resisted the temptation, very real in 2024 and 2025, to ship an "agentic" product that simply pays bills without supervision. Their argument is that finance is the wrong place to let an AI run unattended, and the more interesting work is making humans faster - not removing them.
The unglamorous principle
"AI in finance only works when the humans stay in the loop." It is the company's quiet rebuttal to every demo where a chatbot promises to run your back office while you sleep. Stampli's bet is that the boring answer - assist, do not replace - is also the one that wins.
Why the boring fintech wins the next cycle
The procure-to-pay category is consolidating. Bill.com is one pole. SAP and Oracle are another. A handful of vertical players, including AvidXchange, are a third. Stampli sits in an awkward but defensible middle: too AI-native to be lumped with the legacy ERP add-ons, too embedded in finance plumbing to be dismissed as a generic AI wrapper.
The next cycle in B2B software is, almost certainly, about agents that do real work inside enterprise systems. Stampli has a head start because they have spent a decade learning what work, exactly, an AI agent can do safely inside a finance function - and where it cannot. The list of things Billy will not touch is, in some ways, more interesting than the list of things it will.
Footnotes & small things
- The company is literally named after a stamp - every approval and comment is "stamped" to the invoice.
- Two brothers built it. Eyal runs the company. Ofer writes the code.
- Half the team lives in Mountain View. The other half lives in Israel. Slack does the rest.
- Their AI mascot is named Billy. As in, "the billy." It is on purpose.
- Stampli was doing AI in accounts payable in 2015 - eight years before the rest of the market noticed.
- The Series D was announced one week before the public AI hype cycle peaked. The timing was, depending on whom you ask, lucky or earned.
4:14 p.m., revisited
It is 4:14 p.m. on a Tuesday. The invoice arrives. The department head's phone vibrates - a comment thread, on the invoice itself. Billy has already coded the line items, matched them against an open PO, and flagged one number that looks high. The department head answers in a sentence. The CFO sees the approval at 4:17. The vendor sees the payment scheduled by 4:22.
The hospital's AP clerk, who used to chase that invoice through five inboxes, is on the train home. Whether you find this dramatic depends on how many invoices you have processed in your life. Stampli's bet is that there are more people in that camp than the rest of fintech realized - and that quietly fixing their afternoon is a category worth $85B in invoice value and counting.
Stampli is not loud. It does not need to be. The invoice talks back now. That, on its own, is the story.