Principality Building Society
Principality Building Society is the largest building society in Wales and the sixth largest in the United Kingdom, founded in 1860 and headquartered in Cardiff. It is a mutual, owned by and run for the benefit of its members rather than shareholders, holding total assets of more than £11 billion and operating around 71 branches and agencies alongside internet and telephone channels. Its product range is deliberately narrow - savings, residential mortgages and investments, plus a commercial lending division - and it does NOT offer current or payment accounts. Principality is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the PRA, and is a member of the Building Societies Association. It is NOT one of the nine CMA9 banks mandated to deliver UK Open Banking, and because it holds no payment accounts it falls outside the scope of the PSD2 / OBIE Read/Write (AIS, PIS, CBPII) standard. As of this profile Principality publishes no public developer portal and no confirmed OBIE Open Data API endpoint; the Open Banking API family below is represented as the shared Open Banking Implementation Entity (OBIE) standard for reference only, not as a Principality-operated contract.
More than an index entry, but the surface is still mostly links rather than artifacts — the cohort most likely to move a full band from modest, well-targeted work.
API Evangelist profiles Principality Building Society the way a machine reads it — 6 machine-readable artifacts across 4 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 — Principality Building Society scores 29.8/100 (emerging), with a separate agent-readiness read of 35/100 (agent aware). 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 Principality Building Society
Each block below is one kind of artifact we hold for Principality 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 4
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.
OBIE Open Data API (Shared Standard - Unverified for Principality)
The UK Open Banking Implementation Entity (OBIE) Open Data API standard - public, unauthenticated reference data covering Branches, ATMs, Personal Current Accounts, Business Cur...
OBIE Account & Transaction Information API (AIS - Standard, Out of Scope)
The OBIE Read/Write Account and Transaction Information (AISP) standard for reading account, balance and transaction data. FAPI-secured with OAuth2/OIDC, mutual-TLS and PSD2 str...
OBIE Payment Initiation API (PIS - Standard, Out of Scope)
The OBIE Read/Write Payment Initiation (PISP) standard for initiating domestic, scheduled, standing-order, international and file payments. FAPI-secured with OAuth2/OIDC, mutual...
OBIE Confirmation of Funds API (CBPII - Standard, Out of Scope)
The OBIE Read/Write Confirmation of Funds (CBPII) standard for confirming whether funds are available on a payment account. FAPI-secured with OAuth2/OIDC, mutual-TLS and PSD2 st...
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.
Resources
Every other property we hold for Principality 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.
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 2
Pagination, idempotency, versioning, errors, and events
Access & Security 2
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 4
The organization behind the API
← All providers · Data indexed from github.com/api-evangelist/principality-building-society · machine-readable index on apis.io