GB Bank website screenshot

GB Bank

GB Bank Limited is a UK challenger bank headquartered in Middlesbrough (2 Centre Square) with a London office (73 Brook Street, Mayfair). Wholly owned and privately backed rather than a mutual building society, it secured its full UK banking licence in 2022 and is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the PRA (Financial Services Register number 850286). GB Bank funds SME regional property developers and investors with development finance, buy-to-let and bridging loans (typically between £26k and £5m across underserved UK regions) and funds that lending with retail deposits - fixed-rate bonds, notice accounts and easy-access savings accounts protected by the FSCS up to £85,000, managed through an online portal and a GB Bank mobile app. As a small, non-CMA9 FCA-authorised bank focused on savings and secured lending, GB Bank does not operate a public developer portal or a documented UK Open Banking (OBIE / PSD2) API surface; the Open Banking API families listed here are represented as the shared industry standard the bank would conform to as an FCA-authorised ASPSP, and are unverified for GB Bank pending a confirmed developer portal or Open Data endpoint.

GB Bank publishes 4 APIs on the APIs.io network, including Open Data API, Account and Transaction Information API (AIS), Payment Initiation API (PIS), and 1 more. Tagged areas include Financial Services, Banking, Open Banking, PSD2, and OBIE.

GB Bank’s developer surface includes authentication, support, engineering blog, and 17 more developer resources.

🌐 Visit website 📡 Source on GitHub
37.9/100 thin ▬ flat Agent 58/100 agent ready Full breakdown ↓
scored 2026-07-27 · rubric v0.5
4 APIs
Financial ServicesBankingOpen BankingPSD2OBIEUnited KingdomPaymentsAccount InformationSavingsProperty FinanceSME LendingFintech

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 37.9/100 · thin
Contract Quality 13.5 / 25
Developer Ergonomics 3.5 / 20
Commercial Clarity 4.2 / 20
Operational Transparency 0.0 / 13
Governance 0.0 / 12
Discoverability 10.0 / 10
Agent readiness — 58/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 15 / 15
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 0 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
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/gb-bank: 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 4

Individual APIs this provider publishes, each with its own machine-readable definition.

GB Bank Open Data API

UK Open Banking Open Data API (OBIE standard, v1.3) - the public, unauthenticated reference-data surface for ATMs, Branches, Personal Current Accounts, Business Current Accounts...

GB Bank Account and Transaction Information API (AIS)

UK Open Banking Read/Write Account & Transaction Information API (AISP) - the OBIE standard for accessing account, balance, transaction and statement data with customer consent....

GB Bank Payment Initiation API (PIS)

UK Open Banking Read/Write Payment Initiation API (PISP) - the OBIE standard for initiating domestic, scheduled, standing-order, international and file payments with customer co...

GB Bank Confirmation of Funds API (CBPII)

UK Open Banking Read/Write Confirmation of Funds API (CBPII) - the OBIE standard for confirming whether funds are available on a payment account with customer consent. FAPI-secu...

Security Posture 2

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

Gb Bank Authentication

oauth2 · 2 schemes

SECURITY

Gb Bank Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Gb Bank Scopes

3 scopes · clientCredentials/authorizationCode

3 scopes

SCOPES

Agentic Access 1

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

Gb Bank Agentic Access

86 operations · 20 acting

86 operations · 20 acting

AGENTIC

Resources

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess
 LLMsTxt
LLMsTxt

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Conventions
Conventions
 Idempotency
Idempotency
 ErrorCatalog
ErrorCatalog
 Conformance
Conformance
 DataModel
DataModel

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 3

The organization behind the API

Website
Website
 Blog
Blog
 LinkedIn
LinkedIn

Other 4

Properties that don't map to a standard resource type

Savings
Savings
 MobileApp
MobileApp
 Standard
Standard
 Standard
Standard

Source (apis.yml)

apis.yml Raw ↑ 
aid: gb-bank
url: https://raw.githubusercontent.com/api-evangelist/gb-bank/refs/heads/main/apis.yml
name: GB Bank
kind: company
description: GB Bank Limited is a UK challenger bank headquartered in Middlesbrough (2 Centre Square) with a London office
  (73 Brook Street, Mayfair). Wholly owned and privately backed rather than a mutual building society, it secured its full
  UK banking licence in 2022 and is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct
  Authority and the PRA (Financial Services Register number 850286). GB Bank funds SME regional property developers and investors
  with development finance, buy-to-let and bridging loans (typically between £26k and £5m across underserved UK regions) and
  funds that lending with retail deposits - fixed-rate bonds, notice accounts and easy-access savings accounts protected by
  the FSCS up to £85,000, managed through an online portal and a GB Bank mobile app. As a small, non-CMA9 FCA-authorised bank
  focused on savings and secured lending, GB Bank does not operate a public developer portal or a documented UK Open Banking
  (OBIE / PSD2) API surface; the Open Banking API families listed here are represented as the shared industry standard the
  bank would conform to as an FCA-authorised ASPSP, and are unverified for GB Bank pending a confirmed developer portal or
  Open Data endpoint.
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
tags:
- Financial Services
- Banking
- Open Banking
- PSD2
- OBIE
- United Kingdom
- Payments
- Account Information
- Savings
- Property Finance
- SME Lending
- Fintech
created: '2026-07-23'
modified: '2026-07-23'
specificationVersion: '0.19'
apis:
- aid: gb-bank:gb-bank-open-data-api
  name: GB Bank Open Data API
  description: UK Open Banking Open Data API (OBIE standard, v1.3) - the public, unauthenticated reference-data surface for
    ATMs, Branches, Personal Current Accounts, Business Current Accounts, Unsecured SME Loans and Commercial Credit Cards.
    Represented here as the shared OBIE Open Data Standard; UNVERIFIED for GB Bank - no live Open Data endpoint was confirmed
    on a gbbank.co.uk host (no fabricated base URL).
  humanURL: https://github.com/OpenBankingUK/opendata-api-docs-pub
  baseURL: ''
  tags:
  - Open Data
  - ATMs
  - Branches
  - Reference Data
  - Unauthenticated
  properties:
  - type: OpenAPI
    url: openapi/uk-open-banking-open-data-api-openapi.json
  - type: Documentation
    url: https://github.com/OpenBankingUK/opendata-api-docs-pub
  - type: APIReference
    url: https://github.com/OpenBankingUK/opendata-api-spec-compiled
- aid: gb-bank:gb-bank-account-transaction-information-api
  name: GB Bank Account and Transaction Information API (AIS)
  description: UK Open Banking Read/Write Account & Transaction Information API (AISP) - the OBIE standard for accessing account,
    balance, transaction and statement data with customer consent. FAPI-secured (OAuth2/OIDC, mTLS, PSD2 SCA). Represented
    here as the shared OBIE Read/Write Standard; UNVERIFIED for GB Bank - no GB Bank developer portal or production/sandbox
    base URL was found (no fabricated host).
  humanURL: https://github.com/OpenBankingUK/read-write-api-specs
  baseURL: ''
  tags:
  - Account Information
  - Transactions
  - AISP
  - FAPI
  properties:
  - type: OpenAPI
    url: openapi/uk-open-banking-account-info-api-openapi.yaml
  - type: Documentation
    url: https://standards.openbanking.org.uk/
  - type: APIReference
    url: https://github.com/OpenBankingUK/read-write-api-specs
- aid: gb-bank:gb-bank-payment-initiation-api
  name: GB Bank Payment Initiation API (PIS)
  description: UK Open Banking Read/Write Payment Initiation API (PISP) - the OBIE standard for initiating domestic, scheduled,
    standing-order, international and file payments with customer consent. FAPI-secured (OAuth2/OIDC, mTLS, PSD2 SCA). Represented
    here as the shared OBIE Read/Write Standard; UNVERIFIED for GB Bank - no GB Bank developer portal or base URL was confirmed
    (no fabricated host).
  humanURL: https://github.com/OpenBankingUK/read-write-api-specs
  baseURL: ''
  tags:
  - Payment Initiation
  - Payments
  - PISP
  - FAPI
  properties:
  - type: OpenAPI
    url: openapi/uk-open-banking-payment-initiation-api-openapi.yaml
  - type: Documentation
    url: https://standards.openbanking.org.uk/
  - type: APIReference
    url: https://github.com/OpenBankingUK/read-write-api-specs
- aid: gb-bank:gb-bank-confirmation-of-funds-api
  name: GB Bank Confirmation of Funds API (CBPII)
  description: UK Open Banking Read/Write Confirmation of Funds API (CBPII) - the OBIE standard for confirming whether funds
    are available on a payment account with customer consent. FAPI-secured (OAuth2/OIDC, mTLS, PSD2 SCA). Represented here
    as the shared OBIE Read/Write Standard; UNVERIFIED for GB Bank - no GB Bank developer portal or base URL was confirmed
    (no fabricated host).
  humanURL: https://github.com/OpenBankingUK/read-write-api-specs
  baseURL: ''
  tags:
  - Confirmation of Funds
  - CBPII
  - FAPI
  properties:
  - type: OpenAPI
    url: openapi/uk-open-banking-confirmation-of-funds-api-openapi.yaml
  - type: Documentation
    url: https://standards.openbanking.org.uk/
  - type: APIReference
    url: https://github.com/OpenBankingUK/read-write-api-specs
common:
- type: DomainSecurity
  url: security/gb-bank-domain-security.yml
- type: AgenticAccess
  url: agentic-access/gb-bank-agentic-access.yml
- type: OAuthScopes
  url: scopes/gb-bank-scopes.yml
- type: Authentication
  url: authentication/gb-bank-authentication.yml
- type: Conventions
  url: conventions/gb-bank-conventions.yml
- type: Idempotency
  url: conventions/gb-bank-conventions.yml
- type: ErrorCatalog
  url: errors/gb-bank-problem-types.yml
- type: Conformance
  url: conformance/gb-bank-conformance.yml
- type: DataModel
  url: data-model/gb-bank-data-model.yml
- type: LLMsTxt
  url: llms/gb-bank-llms.txt
- type: Website
  url: https://www.gbbank.co.uk/
- type: Savings
  url: https://www.gbbank.co.uk/savings
- type: MobileApp
  url: https://www.gbbank.co.uk/gb-bank-mobile-app
- type: Support
  url: https://www.gbbank.co.uk/help-and-support/faqs
- type: Blog
  url: https://www.gbbank.co.uk/news
- type: TermsOfService
  url: https://www.gbbank.co.uk/terms
- type: PrivacyPolicy
  url: https://www.gbbank.co.uk/privacy-policy
- type: LinkedIn
  url: https://www.linkedin.com/company/thegbb
- type: Standard
  name: UK Open Banking Open Data Standard
  url: https://github.com/OpenBankingUK/opendata-api-spec-compiled
- type: Standard
  name: UK Open Banking Read/Write API Standard
  url: https://standards.openbanking.org.uk/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com