MSIV Invests in San Rafael's Rivet

Tuesday, November 10, 2026

Since 2021, Marin Sonoma Impact Ventures (MSIV) has invested in early-stage companies across the North Bay. We back founders building category-defining businesses close to home, and we're proud to announce our investment in Rivet, based in San Rafael.

Rivet uses AI to solve a problem that touches almost every business in America, and that almost nobody can see: the hidden cost of accepting credit cards.

Every time you tap a card, the business you're buying from pays a fee. Most people don't realize the fee isn't fixed. It depends on the information that travels with each payment, and when details go missing, which happens constantly, the business pays more. Getting those details right has always taken teams combing through data by hand. Rivet's AI does that work automatically, on every payment, in a fraction of a second.

And as AI starts buying things on our behalf, the information attached to each payment is about to matter more than ever. Rivet is building the layer that gets it right.

Why We Invested

AI finally makes this problem solvable. Think of card fees like the cost of driving a rental car. Part of it is a toll paid to the card networks, like Visa and Mastercard, for using their roads. The bigger part is required insurance, paid to the cardholder's bank. That bank has a split second to decide whether a charge is real or fraud, and it takes the loss if it guesses wrong. Like any insurance, the price depends on your driving record. The more information a business sends with each payment, the safer it looks, and the less it pays.

Here's the catch: the networks set thousands of different prices, the rules change twice a year, and nobody sends a notice. The charges show up weeks later in statements that are nearly impossible to read. Fixing this has always taken a few rare experts reading hundred-row rate sheets and checking payments one by one, and only the biggest companies can afford that team. AI changes the math. It can read the rules, spot what's missing and fix it on every payment, for every business, not just the giants.

AI is also about to make the problem much bigger. AI assistants are starting to shop for us. When an AI books your flight or reorders office supplies, there's no person at the checkout and no signature, just data. The information attached to each payment becomes the whole story, and it decides what the payment costs and whether it goes through at all. The businesses with clean, complete payment data will win. Rivet is built for that world.

The opportunity is enormous. U.S. businesses paid nearly $200 billion in card fees last year, up about 70% since 2019. For most companies, it's their biggest cost after payroll, and those fees end up in the price of everything we buy. Worldwide, card spending passed $50 trillion in 2024 and is on track to top $70 trillion by 2030. Every one of those payments carries data, and every one is priced and approved based on it. Lower fees are where Rivet starts. Higher approval rates and less fraud come from the same fix.

Rivet Co-Founder & CEO Sarah Schaaf has lived this problem. Sarah began her career as a litigator and then became an attorney at Google. In 2014, she left Google to found Headnote, which brought payments online for law firms. Rivet is her fourth company, and Rivet's co-founders worked together in payments before. MSIV was proud to participate as part of Rivet's oversubscribed initial capitalization, led by Precursor Ventures and alongside many of Sarah's past investors backing her once again.

Rivet Co-Founder & CEO Sarah Schaaf delivering an inspiring keynote on her entrepreneurial journey at MSIV's 2023 North Bay NEXT Conference

MSIV Founder & Managing Partner Zachary Kushel sat down with Sarah to discuss Rivet's work to leverage AI to reign in the hidden costs of accepting credit cards.

Q&A with Sarah Schaaf, Co-Founder and CEO of Rivet

Sarah, how does an attorney at Google end up building an AI payments company?

I never planned on payments. I'm the child of two attorneys, and I started my career in litigation before transitioning in-house to Google's legal department. I worked in and around law firms and legal departments most of my life, and no matter the size of the firm or specialty area, the worst part of running a law practice was getting paid. Clients still mailed paper checks, because most payment platforms wouldn't touch lawyers' trust accounts. So in 2014 I left Google to start Headnote and bring payments online for law firms.

Rivet CEO Sarah Schaaf

Headnote ended up going through the strange experience of being acquired twice in two years by two separate private equity firms. Along the way, my team ended up running payments for a whole portfolio of software companies that were part of the private equity rollup. We had a very motivating earnout structure, and I became singularly focused on maximizing our margin on every payment that went over our platform.

And so began my journey into the complex, tedious and manual world of payment cost optimization. Every month we had a team of analysts that went through thousands of transactions one by one, trying to figure out why our fees had changed. Usually a rule had shifted or a detail had stopped coming through, and nobody told us. We did this process month over month, and it became our special sauce. We found real money every time, money that went straight from being categorized as a cost to profit.

Why is AI so central to Rivet?

The tools we built at previous companies worked but only because of the people running them. Someone had to read the card networks' rate sheets, hundreds of rows each, at least twice a year. Someone had to decode messy reports that never looked the same twice and check every payment against rules that kept moving. That's why only the biggest companies do this type of payment optimization well.

Then AI got good enough to do the reading. It can take in a 300-row rate sheet and a messy report and work out what changed, what's missing and what it's costing you. That turns expert judgment into software that runs on every payment, for every company via our proprietary rule engine. That was the light bulb. That's Rivet.

AI changed how we build, too. Work that used to take a team of analysts weeks now runs automatically. A small team can do what used to take a department, and that's exactly what we want for our customers.

What's your vision for Rivet?

Every company that takes cards is quietly running two businesses: the one it set out to build, and a payments business it never planned on. Card fees are usually its biggest cost after payroll, and almost nobody can explain them.

AI agents are about to make this problem much bigger. Soon, a lot of what we buy will be bought by software acting for us. When an agent books the flight, the bank loses most of the signals it uses to tell a real purchase from a risky one. The information riding along with each payment becomes the whole story. Companies that send clean, complete data will get approved more and pay less. Without good data, payment costs will skyrocket.

Today, no single company can see that whole picture. Each processor, card network and bank sees only its own slice. We're starting with lower fees because they're the easiest to measure and a massive pain point for most businesses with meaningful processing volume. Long term, we want to be the layer underneath every payment, made by a person or an agent, that makes sure it carries the information it needs.

What has Rivet accomplished in its first year?

A year ago, we had no office, no website, no product and no customers. Today, we have 100% customer retention, and every customer came from my network or a referral. We've found money left on the table in every audit we've run, usually between 5 and 50 bps. One customer saved nearly $20,000 in its first 30 days after a fix. We've analyzed nearly 20 million payments, became an official Stripe and Adyen partner and filed patents on our core technology. And we raised an oversubscribed round from Precursor Ventures, MSIV and others. I'm especially honored that so many investors from my past companies backed me again.

This is your fourth company. What feels different this time?

My first two companies were venture-backed consumer startups, and neither turned out the way I hoped. I learned a lot from both. Headnote was the first time I built for a world I knew from the inside, and it worked.

The biggest difference now is that I know what I'm walking into. I spent the last few years coaching other founders, and nearly all of my team has built with me before. After years apart, coming to work feels a lot like coming home. We'll still make mistakes. We'll just make new ones. It's just as fun and just as hard as it ever was.

As a North Bay neighbor, what do you love about living and building in Marin?

I fell for Marin when I lived in San Francisco. On foggy days I'd drive across the bridge and find sunshine on the other side. Right before the pandemic, my family moved to San Anselmo. Our street is full of kids riding bikes between houses, and you can hear neighbors laughing in their backyards. It's a great place to raise a family, and it turns out to be a great place to build a company, too.

How do you see the North Bay startup community growing, and what role does MSIV play?

More and more people who've built big things are moving north, and the talent here is real. For a long time, the North Bay has been seen as a place to hike, bike and raise kids, not a place to build a big company. MSIV is changing that, and I want Rivet to be part of the proof that you can do both here.