# Leeds Building Society

**Canonical:** https://apis.io/providers/leeds-building-society/  
**Website:** https://www.leedsbuildingsociety.co.uk/  
**APIs profiled:** 4

Leeds Building Society is the fifth-largest building society in the United Kingdom, a mutual owned by and run for the benefit of its members rather than shareholders. Founded in 1875 and headquartered in Leeds, West Yorkshire, it holds over GBP 31 billion in assets and serves more than 991,000 members, focusing on savings and residential mortgages (including shared-ownership and later-life lending) rather than current accounts. It is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the PRA. Because Leeds Building Society does not provide payment or current accounts, it is not one of the CMA9 mandated banks and is not an Account Servicing Payment Service Provider (ASPSP) under PSD2 / UK Open Banking; it participates in Open Banking as a data consumer (for example using Experian Boost and Account Information data to speed mortgage affordability decisions) rather than as an API provider. As of this review it publishes no public developer portal, no OBIE Open Data endpoint, and no OBIE Read/Write APIs. The OBIE standard specifications below are captured as shared-standard references, not as Leeds Building Society API contracts.

## Kin Score — 28.7 / 100 (thin)

Scored 2026-08-19 under rubric 0.12.0. Trend: rising (+5.6 from 23.1).

| Facet | Score |
|---|---|
| Discoverability | 72.2 |
| Contract Quality | 37.1 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 10.5 |
| Developer Ergonomics | 7.1 |
| Commercial Clarity | 57.1 |
| Access Clarity | 57.1 |

Regulatory layer — **Banking & Open Finance**: 17.7 (matched via tags).

## Agent readiness — 18.4 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| Reversibility Documented | na |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | na |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | na |

## Access

No public API program — onboarding: unknown, pricing: unknown, trial: no (confidence: high).

## APIs (4)

- **OBIE Open Data API (shared standard)** — The UK Open Banking (OBIE) Open Data API standard for public, unauthenticated reference data - ATM locations, branch locations, personal and business current accounts, unsecured...
- **OBIE Account and Transaction Information API (AIS, shared standard)** — The OBIE Read/Write Account and Transaction Information (AIS) standard for retrieving account, balance, transaction, and beneficiary data with customer consent, secured with FAP...
- **OBIE Payment Initiation API (PIS, shared standard)** — The OBIE Read/Write Payment Initiation (PIS) standard for initiating domestic, scheduled, standing-order, international, and file payments with customer consent, secured with FA...
- **OBIE Confirmation of Funds API (CBPII, shared standard)** — The OBIE Read/Write Confirmation of Funds (CBPII) standard for confirming whether funds are available on a payment account, secured with FAPI OAuth2/OIDC, mutual-TLS, and PSD2 s...

## Security (1)

- **Leeds Building Society Domain Security** — TLSv1.3 · DNSSEC · DMARC

## Tags

Financial Services, Banking, Building Society, Mutual, Savings, Mortgages, Open Banking, PSD2, OBIE, United Kingdom

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/leeds-building-society/). Scores are computed from the provider's own public artifacts under a published rubric.