Yorkshire Building Society website screenshot

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.

Yorkshire Building Society publishes 4 APIs on the APIs.io network, including Account Information API, Payment Initiation API, Confirmation of Funds API, and 1 more. Tagged areas include Financial-Services, Banking, Building Society, Open Banking, and PSD2.

The Yorkshire Building Society catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Yorkshire Building Society’s developer surface includes authentication, sandbox, documentation, getting-started guide, support, and 24 more developer resources.

🌐 Visit website 📡 Source on GitHub
48.4/100 developing ▬ flat Agent 42/100 agent ready Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0
6 APIs 1 MCP Servers
Financial-ServicesBankingBuilding SocietyOpen BankingPSD2OBIEFAPIUnited KingdomPaymentsAccount InformationFintech

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0
Composite quality — 48.4/100 · developing
Contract Quality 12.3 / 21
Developer Ergonomics 9.6 / 17
Access Clarity 3.6 / 17
Operational Transparency 0.9 / 11
Contract Governance 3.1 / 10
Discoverability 7.9 / 9
Regulatory Posture 9.1 / 15
Agent readiness — 42/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
Documented Reversibility 0 / 6
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 9 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 6 / 6
Agent Skills 5 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Regulatory Posture applies to this provider. Its tags matched the Banking & Open Finance regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.
The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/yorkshire-building-society: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 6

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 that expose these APIs to AI agents.

Yorkshire Building Society MCP Server

MCP SERVER

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Yorkshire Building Society Events Webhooks

ASYNCAPI

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Yorkshire Building Society Authentication

oauth2/mutualTLS · 3 schemes

SECURITY

Yorkshire Building Society Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Yorkshire Building Society Scopes

4 scopes

4 scopes

SCOPES

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Yorkshire Building Society Agentic Access

78 operations · 23 acting

78 operations · 23 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

Sandbox
Sandbox
 DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess
 WellKnown
WellKnown
 MCPServer
MCPServer
 AgentSkill
AgentSkill
 LLMsTxt
LLMsTxt

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conformance
Conformance
 ErrorCatalog
ErrorCatalog
 Lifecycle
Lifecycle
 Conventions
Conventions
 Idempotency
Idempotency
 DataModel
DataModel
 Webhooks
Webhooks

Scroll for all 7

Build 1

SDKs, sample code, and the tooling you integrate with

ToolCrosswalk
ToolCrosswalk

Access & Security 3

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity
 OAuthScopes
OAuthScopes
 Authentication
Authentication

Operate 1

Status, limits, changes, and where to get help

Support
Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy

Company 2

The organization behind the API

Website
Website
 LinkedIn
LinkedIn

Other 4

Properties that don't map to a standard resource type

Overlay
Overlay
 Overlay
Overlay
 Overlay
Overlay
 Overlay
Overlay

Source (apis.yml)

apis.yml Raw ↑ 
aid: yorkshire-building-society
url: https://raw.githubusercontent.com/api-evangelist/yorkshire-building-society/refs/heads/main/apis.yml
name: Yorkshire Building Society
kind: company
description: 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.
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
tags:
- Financial-Services
- Banking
- Building Society
- Open Banking
- PSD2
- OBIE
- FAPI
- United Kingdom
- Payments
- Account Information
- Fintech
tags_raw:
- Financial Services
- Banking
- Building Society
- Open Banking
- PSD2
- OBIE
- FAPI
- United Kingdom
- Payments
- Account Information
- Fintech
created: '2026-07-23'
modified: '2026-07-23'
specificationVersion: '0.23'
apis:
- aid: yorkshire-building-society:ybs-account-information-api
  name: Yorkshire Building Society Account Information API
  description: OBIE Read/Write Account and Transaction Information (AISP) API v3.1.2 - lets FCA-authorised account information
    service providers retrieve account, balance, transaction, beneficiary, standing order, direct debit, product, party and
    statement data for consenting YBS and Chelsea Building Society payment-account customers. FAPI-secured (OAuth2/OIDC, mTLS,
    PSD2 SCA).
  humanURL: https://developers.ybs.co.uk/api-catalog/account-information-api
  baseURL: https://ob-ybs.api.ybs.co.uk/open-banking/v3.1/aisp
  tags:
  - Account Information
  - AISP
  - Open Banking
  properties:
  - type: OpenAPI
    url: openapi/yorkshire-building-society-account-information-api-openapi.yaml
  - type: Documentation
    url: https://developers.ybs.co.uk/api-catalog/account-information-api
  - type: APIReference
    url: https://developers.ybs.co.uk/api-catalog/account-information-api
  - type: GettingStarted
    url: https://developers.ybs.co.uk/docs/getting-started
- aid: yorkshire-building-society:ybs-payment-initiation-api
  name: Yorkshire Building Society Payment Initiation API
  description: 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 payment consents and initiate payments from consenting YBS
    and Chelsea Building Society accounts. FAPI-secured (OAuth2/OIDC, mTLS, PSD2 SCA).
  humanURL: https://developers.ybs.co.uk/api-catalog/payment-initiation-api-0
  baseURL: https://ob-ybs.api.ybs.co.uk/open-banking/v3.1/pisp
  tags:
  - Payment Initiation
  - PISP
  - Payments
  properties:
  - type: OpenAPI
    url: openapi/yorkshire-building-society-payment-initiation-api-openapi.yaml
  - type: Documentation
    url: https://developers.ybs.co.uk/api-catalog/payment-initiation-api-0
  - type: APIReference
    url: https://developers.ybs.co.uk/api-catalog/payment-initiation-api-0
  - type: GettingStarted
    url: https://developers.ybs.co.uk/docs/getting-started
- aid: yorkshire-building-society:ybs-confirmation-of-funds-api
  name: Yorkshire Building Society Confirmation of Funds API
  description: 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 specified amount is available on a consenting YBS or
    Chelsea Building Society account. FAPI-secured (OAuth2/OIDC, mTLS, PSD2 SCA).
  humanURL: https://developers.ybs.co.uk/api-catalog/confirmation-funds-api
  baseURL: https://ob-ybs.api.ybs.co.uk/open-banking/v3.1/cbpii
  tags:
  - Confirmation of Funds
  - CBPII
  - Open Banking
  properties:
  - type: OpenAPI
    url: openapi/yorkshire-building-society-confirmation-of-funds-api-openapi.yaml
  - type: Documentation
    url: https://developers.ybs.co.uk/api-catalog/confirmation-funds-api
  - type: APIReference
    url: https://developers.ybs.co.uk/api-catalog/confirmation-funds-api
  - type: GettingStarted
    url: https://developers.ybs.co.uk/docs/getting-started
- aid: yorkshire-building-society:ybs-event-subscriptions-api
  name: Yorkshire Building Society Event Subscriptions API
  description: 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 notifications (for example consent revocation) for YBS and Chelsea
    Building Society Open Banking resources. FAPI-secured (OAuth2/OIDC, mTLS).
  humanURL: https://developers.ybs.co.uk/api-catalog/event-subscriptions-api
  baseURL: https://ob-ybs.api.ybs.co.uk/open-banking/v3.1/aisp
  tags:
  - Event Subscriptions
  - Notification
  - Open Banking
  tags_raw:
  - Event Subscriptions
  - Notifications
  - Open Banking
  properties:
  - type: OpenAPI
    url: openapi/yorkshire-building-society-event-subscriptions-api-openapi.yaml
  - type: Documentation
    url: https://developers.ybs.co.uk/api-catalog/event-subscriptions-api
  - type: APIReference
    url: https://developers.ybs.co.uk/api-catalog/event-subscriptions-api
  - type: GettingStarted
    url: https://developers.ybs.co.uk/docs/getting-started
- aid: yorkshire-building-society:ybs-dynamic-client-registration-api
  name: Yorkshire Building Society Dynamic Client Registration API
  description: 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 Building Society authorization servers. Part of the
    OBIE security profile; secured with mTLS and PS256-signed JWTs.
  humanURL: https://developers.ybs.co.uk/api-catalog/dynamic-client-registration-api-0
  baseURL: https://ob-ybs.api.ybs.co.uk/register
  tags:
  - Dynamic Client Registration
  - Security
  - Authentication
  tags_raw:
  - Dynamic Client Registration
  - Security
  - OAuth
  properties:
  - type: Documentation
    url: https://developers.ybs.co.uk/api-catalog/dynamic-client-registration-api-0
  - type: APIReference
    url: https://developers.ybs.co.uk/api-catalog/dynamic-client-registration-api-0
  - type: GettingStarted
    url: https://developers.ybs.co.uk/docs/getting-started
- aid: yorkshire-building-society:ybs-generate-access-token-api
  name: Yorkshire Building Society Generate Access Token API
  description: 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 tokens against the YBS and Chelsea Building Society
    authorization servers. FAPI-secured with mTLS and PS256-signed JWTs.
  humanURL: https://developers.ybs.co.uk/api-catalog/generate-access-token-api
  baseURL: https://ob-ybs.api.ybs.co.uk/token
  tags:
  - Authentication
  - Token
  - Security
  tags_raw:
  - OAuth
  - Token
  - Security
  properties:
  - type: Documentation
    url: https://developers.ybs.co.uk/api-catalog/generate-access-token-api
  - type: APIReference
    url: https://developers.ybs.co.uk/api-catalog/generate-access-token-api
  - type: GettingStarted
    url: https://developers.ybs.co.uk/docs/getting-started
common:
- type: AgenticAccess
  url: agentic-access/yorkshire-building-society-agentic-access.yml
- type: DomainSecurity
  url: security/yorkshire-building-society-domain-security.yml
- type: OAuthScopes
  url: scopes/yorkshire-building-society-scopes.yml
- type: Authentication
  url: authentication/yorkshire-building-society-authentication.yml
- type: WellKnown
  url: well-known/yorkshire-building-society-well-known.yml
- type: Conformance
  url: conformance/yorkshire-building-society-conformance.yml
- type: ErrorCatalog
  url: errors/yorkshire-building-society-problem-types.yml
- type: Lifecycle
  url: lifecycle/yorkshire-building-society-lifecycle.yml
- type: Conventions
  url: conventions/yorkshire-building-society-conventions.yml
- type: Idempotency
  url: conventions/yorkshire-building-society-conventions.yml
- type: Sandbox
  url: sandbox/yorkshire-building-society-sandbox.yml
- type: DataModel
  url: data-model/yorkshire-building-society-data-model.yml
- type: Webhooks
  url: asyncapi/yorkshire-building-society-events-webhooks.yml
- type: MCPServer
  url: mcp/yorkshire-building-society-mcp.yml
- type: ToolCrosswalk
  url: mcp/yorkshire-building-society-tool-crosswalk.yml
- type: AgentSkill
  url: skills/_index.yml
- type: LLMsTxt
  url: llms/yorkshire-building-society-llms.txt
- type: Overlay
  name: Account Information API overlay
  url: overlays/yorkshire-building-society-account-information-api-overlay.yaml
- type: Overlay
  name: Payment Initiation API overlay
  url: overlays/yorkshire-building-society-payment-initiation-api-overlay.yaml
- type: Overlay
  name: Confirmation of Funds API overlay
  url: overlays/yorkshire-building-society-confirmation-of-funds-api-overlay.yaml
- type: Overlay
  name: Event Subscriptions API overlay
  url: overlays/yorkshire-building-society-event-subscriptions-api-overlay.yaml
- type: Website
  url: https://www.ybs.co.uk/
- type: DeveloperPortal
  url: https://developers.ybs.co.uk/
- type: Documentation
  url: https://developers.ybs.co.uk/docs/getting-started
- type: GettingStarted
  url: https://developers.ybs.co.uk/docs/getting-started
- type: Support
  url: https://developers.ybs.co.uk/support
- type: TermsOfService
  url: https://developers.ybs.co.uk/legal
- type: PrivacyPolicy
  url: https://developers.ybs.co.uk/privacy-policy
- type: LinkedIn
  url: https://www.linkedin.com/company/yorkshire-building-society
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com