Yorkshire Building Society
Yorkshire Building Society (YBS) is a UK mutual building society founded in 1864 and headquartered in Bradford, West Yorkshire. As a member-owned mutual rather than a shareholder-owned bank, it is owned by and run for the benefit of its savers and borrowers, with more than three million customers and around £66 billion in assets across the YBS Group, which trades under the Yorkshire Building Society, Chelsea Building Society (CBS), Norwich & Peterborough and Accord Mortgages brands. YBS is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the PRA as an FCA-authorised ASPSP. Although it is not one of the CMA9 banks mandated to build Open Banking, YBS is a voluntary participant in the UK Open Banking / PSD2 ecosystem and operates a public developer portal at developers.ybs.co.uk that documents its OBIE Read/Write API family - Account Information (AIS), Payment Initiation (PIS), Confirmation of Funds (CBPII), Event Subscriptions, Dynamic Client Registration, and token issuance - conformant to the Open Banking Implementation Entity (OBIE) Read/Write Data API Standard v3.1.2. Access to the production and sandbox surfaces (ob-ybs.api.ybs.co.uk / ob-che.api.ybs.co.uk and the matching sandbox hosts) is secured with FAPI-grade OAuth2/OIDC, PSD2 strong customer authentication, mutual-TLS transport authentication and PS256-signed JWTs, and is available to FCA-authorised third-party providers holding eIDAS/OBIE certificates.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles Yorkshire Building Society the way a machine reads it — 12 machine-readable artifacts across 6 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Yorkshire Building Society scores 47.4/100 (developing), with a separate agent-readiness read of 84/100 (agent native). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Yorkshire Building Society
Each block below is one kind of artifact we hold for Yorkshire Building Society. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 6
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Yorkshire Building Society Account Information API
OBIE Read/Write Account and Transaction Information (AISP) API v3.1.2 - lets FCA-authorised account information service providers retrieve account, balance, transaction, benefic...
Yorkshire Building Society Payment Initiation API
OBIE Read/Write Payment Initiation (PISP) API v3.1.2 - lets FCA-authorised payment initiation service providers set up domestic single, scheduled, standing-order and file paymen...
Yorkshire Building Society Confirmation of Funds API
OBIE Read/Write Confirmation of Funds (CBPII) API v3.1.2 - lets FCA-authorised card-based payment instrument issuers set up a funds confirmation consent and confirm whether a sp...
Yorkshire Building Society Event Subscriptions API
OBIE Read/Write Event Subscriptions API v3.1.2 - lets an onboarded TPP create, read and delete event subscriptions so it can receive aggregated-polling and real-time event notif...
Yorkshire Building Society Dynamic Client Registration API
OBIE Dynamic Client Registration (DCR) API v3.1 - lets an FCA-authorised TPP present its OBIE/eIDAS software statement and register a client application with the YBS and Chelsea...
Yorkshire Building Society Generate Access Token API
OBIE token endpoint (Generate Access Token API v3.1.0) - the OAuth2/OIDC token endpoint used by onboarded TPPs to exchange authorization codes and client credentials for access ...
MCP Servers 1
Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
yorkshire-building-society-mcp.yml
MCP SERVEREvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Security Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Scopes 1
OAuth scopes are the vocabulary of least-privilege access. Profiling them shows exactly what an integration — or an agent acting on a user's behalf — is allowed to do.
OAuth scopes governing access to this provider's APIs.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Yorkshire Building Society — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 3
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 5
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 7
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 7 ·
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 3
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 2
Pricing, plans, and the legal terms of use
Company 2
The organization behind the API
Other 4
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/yorkshire-building-society · machine-readable index on apis.io