BIAN, the Banking Industry Architecture Network, is an independent not-for-profit standards association of banks, software vendors, service providers and consultancies that defines a reference architecture for banking — the Service Landscape, which breaks a bank into service domains — and publishes semantic APIs for those domains. Release 14.0 (March 2026) ships 258 service-domain APIs as OpenAPI 3 and AsyncAPI 3 definitions, in a BIAN-object-model form and an ISO 20022-extended form annotated for domain-driven design, published on GitHub under Apache 2.0.
BIAN
BIAN takes on the problem underneath most bank integration work: every bank describes itself differently, so every core-banking replacement, vendor integration and partner API starts with a mapping exercise. BIAN’s answer is a shared reference model of what a bank does — the Service Landscape, which decomposes banking into service domains such as current accounts, payment execution, customer offers or collateral management — and a set of semantic APIs, one per service domain, so that a bank and its vendors can agree on boundaries and names before they agree on payloads.
It is run as an independent, not-for-profit association. Its site lists 113 members — 40 banks and 59 software partners — and 18 active working groups, and says its portal holds 250 APIs and more than 5,000 service domains, available to members and non-members.
- Service domains as the unit of design - The Service Landscape is the model; each service domain is a bounded capability with its own API. BIAN’s Coreless Banking initiative builds on it, aiming at interoperable banking microservices that can replace monolithic cores piece by piece.
- OpenAPI and AsyncAPI, in the open - The semantic APIs are published at bian-official/public under Apache 2.0 (213 stars, releases 9.1 through 14.0). Release 14.0 carries 258 APIs in four forms: OpenAPI 3 and AsyncAPI 3, each in a BIAN-object-model version and an ISO 20022-extended version annotated for domain-driven design.
- Service Landscape 14.0 - Announced on 13 March 2026, it strengthens alignment with ISO 20022 and formally extends BIAN’s standards work into payments and insurance, toward one reference model across financial services.
- Certification and training - BIAN runs a foundation certification programme for practitioners alongside the model.
Where it sits. BIAN is an internal architecture standard for how a bank organises its capabilities and the interfaces between them, which makes it a different animal from the open-banking standards that define what a bank exposes to third parties — FDX, the UK Open Banking Standard, Berlin Group NextGenPSD2 and FAPI for their security profile. The two meet at ISO 20022, which BIAN’s 14.0 APIs now extend and which carries most of the world’s payment messaging.
