Open Banking API Aggregation

The necessity of an API normalization layer in a fragmented regulatory environment.

The Fragmentation Reality

The PSD2 directive mandated that European banks open APIs, but it did not strictly enforce a single standard. Consequently, the Berlin Group standard, the STET standard (France), and the Polish API standard all differ dramatically in payload structure, authentication, and error handling.

Attempting to integrate directly with 4,000+ European banks is a Sisyphean engineering task. A bank in Germany might require eIDAS QWAC certificates and handle OAuth2 differently than a bank in Spain.

The Pisria Normalization Layer

Pisria acts as an aggregator. We maintain the underlying mTLS connections, handle certificate renewals, and map divergent bank schemas into a single, unified REST API.

// You call one endpoint:
POST /v1/payments/initiate

// We handle:
-> eIDAS Certificate Mutual TLS negotiation
-> Bank-specific payload transformation (STET vs Berlin Group)
-> Asynchronous polling or webhook registration with the bank
-> Idempotency and error translation
        

Common Mistakes

Engineering teams frequently underestimate the maintenance burden. Even if you manage to integrate the top 5 banks directly, banks update their APIs frequently, breaking integrations. Relying on an aggregator like Pisria shifts the maintenance risk away from your core product team.