Co-founder & CEO · Lago · YC S21 · San Francisco
Anh-Tho
Chuong
The woman who turned a failed Y Combinator pitch into the open-source billing layer running Mistral AI, Groq, and PayPal.
Photo: TechCrunch
Co-founder & CEO · Lago · YC S21 · San Francisco
The woman who turned a failed Y Combinator pitch into the open-source billing layer running Mistral AI, Groq, and PayPal.
Photo: TechCrunch
Lago powers billing for
The Story
Her father arrived in Réunion - a French island of volcanoes and sugar cane in the Indian Ocean - as a refugee. He had fled Vietnam during the war and found a place to land as a physician. Anh-Tho Chuong grew up 9,000 kilometers from Silicon Valley, surrounded by the Indian Ocean, and still managed to become the CEO building the billing infrastructure that Mistral AI runs its invoices on.
That distance matters. It shaped something in her - a willingness to travel toward the hard problem, not away from it. Billing is the plumbing nobody wants to talk about until it breaks. Anh-Tho built a company to fix it anyway.
After preparatory classes in Paris - first a B/L track in social sciences, then HEC Stanislas - she entered ESCP Business School. What followed was a textbook operator progression: management consultant at McKinsey, head of strategic projects at Mailjet (the eFounders email startup later acquired by Mailgun), then a strategic role at Weebly for the French market expansion.
None of it was the main event. The main event was Qonto.
In September 2016, Anh-Tho joined the fintech startup as employee number one. The founders were still building the MVP. She walked in and built Qonto's entire growth marketing division from a blank slate, and stayed for five years as VP Growth, scaling the company's ARR from zero to tens of millions of euros. She wasn't just running growth - she was figuring out what growth even meant for a neobank in France, a category that barely existed.
By 2021 she knew enough. She knew what it took to scale a product with complex pricing. She knew how broken the billing layer underneath every SaaS company actually was. And she had earned a seat at Y Combinator.
"The billing infrastructure hasn't been updated in decades. There's no reason it should be a black box." - Anh-Tho Chuong, Co-founder & CEO of Lago
The Pivot
In the summer of 2021, Anh-Tho and her co-founder Raffi Sarkissian arrived at Y Combinator with a data project - something in the vein of "Zapier for marketing teams." It was a reasonable idea. It was also wrong.
What happened inside YC is the kind of thing that sounds obvious only in retrospect. Talking to developers, reading Hacker News threads, listening to what people actually complained about - billing kept coming up. Not sometimes. Constantly. Developers hated building it. Finance teams hated managing it. Companies hated being locked into Stripe's pricing model with no way out.
The pivot wasn't a crisis. It was recognition. Anh-Tho had spent five years at Qonto building on top of exactly this broken infrastructure. She knew what it felt like from the inside. The data project got shelved. Lago got born.
The original instinct - to make complex workflows transparent and configurable - survived the pivot. It just moved from marketing automation to billing infrastructure. And billing infrastructure, it turned out, was a much larger problem.
The Philosophy
Most billing platforms are SaaS businesses selling a black box. You send your usage data in, you get invoices out, and you trust that whatever happens in between is correct. For a startup processing a few thousand dollars a month, that's fine. For Groq or Mistral AI running inference at scale, it's a liability.
Lago's answer was radical transparency: put the entire billing engine on GitHub. Let developers read the code, fork it, run it themselves if they want. The business model is cloud hosting and support for companies that don't want to manage it - but the software itself is public.
Nine thousand GitHub stars later, the bet looks right. The open-source repository became Lago's distribution engine. Developers discovered it organically, tried it, and brought it to their companies. Mistral AI runs on it. Groq runs on it. PayPal - not exactly a startup starved for engineering resources - chose it.
"Open source isn't just a distribution strategy," she has said. "It's a trust strategy. Developers need to see what's running their money." In an industry built on opacity, that sentence is a market position.
Career Arc
What They're Building
"We started as a data project at Y Combinator, but billing kept coming up as the biggest pain point for developers." - Anh-Tho Chuong
Beyond Lago
Running a Series A company with 53 employees is a full-time job. It doesn't leave much room for side projects. And yet Anh-Tho has built a meaningful portfolio of angel investments in the companies she believes should exist.
She backed Hugging Face before it became the defining platform for open-source AI - and before it became one of the most valuable technology companies in Europe. The pattern is consistent: she invests in companies building infrastructure that developers need but vendors don't want to provide.
Sifted has written about her as a representative of the "operator angel" archetype - founders and operators who invest not just capital but earned knowledge. She brings GTM intuition from Qonto, infrastructure thinking from Lago, and the financial discipline of someone who has lived through the full lifecycle of a venture-backed company.
Her portfolio spans fintech across multiple continents: Payhippo in Africa, Karbon Card, Djamo. Collaboration infrastructure: Cycle App, Claap, Crew. Developer tools: Anchor (YC S22), Easop. She is also a Limited Partner in Orange DAO, the Web3 fund created by YC alumni.
+ LP at Orange DAO
Lago's Tech Stack
Voice
Guest contributor at TechCrunch is a designation that gets handed out sparingly. Anh-Tho has earned it. She writes about billing, about the economics of usage-based pricing, about what operators actually learn building companies with complex monetization models.
On Medium and Substack, she shares the kind of operational knowledge that most founders keep internal - how to think about growth as a system, what she learned scaling Qonto's acquisition engine, why European tech deserves a different narrative than the one it usually gets in the American press.
She has spoken on podcasts including the Inspire Greatness series (PeopleThriver) and the SaaS Connection podcast, where she broke down the YC pivot story and what it actually feels like to throw away a concept mid-program and start over. In French: "réaliser un pivot après avoir fait YC" - pivot after doing YC. In practice: one of the harder things a founder can do, and she did it inside a 12-week program.
The consistent theme across everything she publishes: infrastructure should be transparent, pricing should be flexible, and developers deserve better tools than the industry has historically given them.
There is also something in the writing about Europe. She is a French founder who went through Y Combinator - one of a relatively small cohort of European operators who made it through the American program and came back to build in Paris. She writes, sometimes, about what that means. About what European tech lacks and what it has in abundance. About why the operator angle matters - the idea that the best investors in early-stage B2B SaaS are often the people who have already done the job.
The INFJ personality type - the rarest of the Myers-Briggs types, shared with about 1-2% of the population - is not something she hides. It shows in the writing: systematic, vision-oriented, convinced that systems matter more than individual moments of inspiration. Lago is a systems bet. Open source is a systems bet. The angel portfolio is a systems bet. The pattern holds.
Scrapbook
What's Next
The goal Anh-Tho has articulated is direct: make Lago the default open-source billing layer for every company that monetizes software. Not the biggest. Not the most funded. The default - which in infrastructure means the option developers reach for first, before they've even decided whether to buy or build.
With Mistral AI and Groq already on the platform - companies defining the frontier of AI infrastructure - she is making a bet that usage-based billing for AI services will become one of the defining pricing challenges of the next decade. Lago wants to be the layer underneath all of it. Transparent. Configurable. No black boxes.
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