Defacto goes live on Mambu Payments for SME lending at scale

Defacto, the ACPR-licensed B2B lending platform, has gone live on Mambu Payments with SEPA connectivity, automating the disbursement and repayment flows that underpin its receivables financing product for small and medium-sized enterprises. The move, announced on 12 August 2026, positions Mambu's composable payments layer as a bridge between regulated fintechs and the tier-one banking infrastructure they rely on to operate at institutional scale.

The integration is notable for what it deliberately avoids. Rather than adopting a traditional Banking-as-a-Service model, which typically requires a fintech to open new accounts with a provider's custodian bank, Defacto retains its existing accounts at its institutional banking partner and automates the payment operations layer on top of them via a single REST API. The distinction matters: composable infrastructure that sits alongside existing banking relationships is increasingly preferred by regulated lenders that cannot afford to rebuild their banking setup from scratch each time they add a partner.

From pilot to production in six months

Defacto moved from initial product scoping with Mambu in July 2025 to beta launch in November 2025 and full production in January 2026, a timeline that illustrates how API-first payment rails can compress go-to-market cycles that once took years of bespoke integration work. The company has financed more than €1.5 billion for over 25,000 SMEs across five European markets since launching in 2021, and the Mambu architecture is already being extended to a second institutional partner.

Jordane Giuly, CEO and co-founder of Defacto, said: "Mambu Payments allowed us to focus our engineering efforts on delivering value for our customers rather than building and maintaining complex banking connectivity. The result is a flexible payments foundation that supports our current programmes while giving us the confidence to expand to additional partners in the future."

The convergence angle: embedded finance meets institutional infrastructure

The Defacto-Mambu partnership is a small but instructive data point in a larger structural shift. Embedded finance, which began life as a consumer-facing phenomenon, is now scaling into regulated B2B and institutional territory, and the bottleneck has moved from product design to payment infrastructure. The ability to automate SEPA flows through a reusable, composable layer, rather than commissioning bespoke connectivity projects for every new banking partner, is becoming a genuine competitive differentiator for fintechs seeking to grow institutional distribution.

This has capital-allocation implications that reach beyond payments technology. European institutional banks are under pressure to modernise their SME lending operations without assuming the regulatory and balance-sheet risk of building proprietary fintech capabilities. Partnering with ACPR-licensed lenders such as Defacto, underpinned by cloud-native payment infrastructure from vendors such as Mambu, offers a capital-light route to embedded SME credit. As that model matures, it is likely to attract attention from private credit funds and corporate balance sheets looking for yield in the SME lending stack, a segment where traditional bank penetration remains structurally thin across France and the broader eurozone.

Mambu currently counts more than 260 customers in over 65 countries, including Western Union, N26, ABN AMRO and Commonwealth Bank of Australia. Its growing payments footprint in Europe positions it as infrastructure-layer competition for both legacy core-banking vendors and the newer BaaS providers that have struggled to retain fintech clients reluctant to sacrifice their existing banking relationships. Whether that positioning translates into pricing power in a market crowded with composable-finance platforms remains an open question for investors tracking the sector.