Anne-Sybille Pradelles on Scaling Open-Source Financial Infrastructure

Formance CEO Anne-Sybille Pradelles recently joined her friend Anh-Tho Chuong, CEO of Lago, on How They Build, a podcast hosted by Timothé Frin. The two founders shared their experiences building mission-critical fintech infrastructure from Europe to the US, and their conversation highlighted the unique challenges of scaling in such a demanding space.

Read on for a synopsis of their conversation.

Open Source as a Foundation of Trust

Anne-Sybille underscored why Formance was open source from day one: In financial infrastructure, transparency and auditability are essential. “Our early users told us: if it’s not open source, we won’t even consider it,” she explained. Being open source gives buyers confidence that Formance does what it says.

Building Systems That Can’t Fail

Together with Anh-Tho, Anne-Sybille pointed out that financial infrastructure doesn’t allow for “minimum viable products.” The systems they build handle core financial flows, so quality assurance, external testing, and reliability are baked into every release. Unlike consumer apps, there’s no room to move fast and break things—financial infrastructure must be designed slowly and intentionally.

Finding the Right Growth Engine

Inbound marketing and developer interest initially fueled growth for both Lago and Formance. But Anne-Sybille explained how Formance recognized the limits of inbound alone. The company is now running verticalized outbound campaigns with a GTM agency to systematically reach the right prospects and drive predictable growth.

Expanding to the US Market

Anne-Sybille also discussed the leap from Europe to the US, a move that demands higher investment, stronger compliance, and local credibility. With SOC2 certifications and a 10-person GTM team in the works, Formance is preparing to meet those expectations head-on.

Turning Customers into Growth Partners

One of Anne-Sybille’s strongest insights was around leveraging early customers as growth engines. She described how Formance embedded case studies and public endorsements into early contracts, ensuring every new logo helped bring in the next. “Every new deal helps close the next one,” she said. Logos aren’t trophies, they’re lead generators.

Why This Matters

The conversation between Anne-Sybille and Anh-Tho revealed a shared philosophy: Building fintech infrastructure isn’t about speed, it’s about trust. Both founders are redefining what it means to scale open source, compliance-ready, customer-centric products in one of the world’s most competitive markets.