From Twilio to Prelude: How Finfrog Reaches Its Customers at the Right Moment for 45% Less

Finfrog is a pioneer in short-term consumer credit in France, combining artificial intelligence and Open Banking to make everyday financing simple and accessible. With loans from €100 to €1,000, Finfrog helps customers handle unexpected expenses and fund everyday needs. Since 2016, the company has financed over half a million loans.

In consumer lending, reaching customers at the right moment matters. From verifying a borrower's phone number at onboarding, to collecting a loan agreement signature, to sending a repayment reminder, these messages need to arrive reliably, at the right time, to the right person. Transactional SMS is that channel, and the quality of that infrastructure directly affects the customer experience.

Enter Prelude.

Together with Valentin Duboscq, Lead Front-End Engineer at Finfrog, we will take a look at how the company leveraged Prelude to gain full visibility into its transactional SMS while cutting costs by nearly 50%.

The Challenge: Sending the Right Message at the Right Time

Like many fintechs, Finfrog started with Twilio as its SMS provider. It worked, but as the team looked more closely at their setup, two things stood out: cost and visibility.

Transactional messages are at the core of Finfrog's customer communication. At every step of the loan journey, from application updates to repayment alerts, customers rely on receiving accurate, timely information. "We were trying to be more efficient, so cost and visibility were both a priority."

Choosing Prelude: A No-Brainer Switch

Valentin came across Prelude while looking for a more cost-effective alternative. The pitch was simple: better pricing, clear visibility, and a one-line SDK swap for developers.

I decided to try Prelude because I knew it was cost-effective. It works as well as other solutions and it's a drop-in replacement for the tech people.

The migration was handled incrementally. Finfrog used a feature flag to gradually route traffic to Prelude before switching over fully. The process was smooth and required minimal engineering effort.

It was just a one-line replacement of the oldSDK. We used a feature flag at first to start incrementally, but we switched fully to Prelude very quickly after that.

45% Cost Reduction

The impact was immediate and measurable. Switching from a pay-as-you-go credit model to an annual contract with Prelude brought Finfrog's SMS bill down by nearly 45%.

We have around a 45% gain on cost. It was a no-brainer.

For a company preparing to enter a new scaling phase, that kind of efficiency at scale makes a real difference.

Visibility That Actually Means Something

Beyond cost, what Finfrog gained with Prelude was clarity. The updated dashboard gave the team a direct view into what was being sent, at what cost, and to which numbers."The old dashboard was quite complicated to navigate. The new one is much clearer. We can create templates, watch costs easily, see cost by phone number, and monitor segments to reduce costs even more."

For a team sending transactional messages to thousands of customers, being able to monitor delivery and optimize spend without extra tooling is exactly the kind of operational control that supports growth.

Looking Ahead

Finfrog is entering a new chapter. With institutional backing replacing its previous crowdfunding model, the company is positioned for strong, controlled expansion in the French market. More customers means more transactional volume, and ensuring every message reaches the right person at the right time remains central to the experience.

Prelude is already in place as that foundation.

Valentin puts it simply:

It works as well as Twilio and it's super cost-effective. Looking back a year after implementing Prelude, we’re happy with our choice!