aid: mettle
url: https://raw.githubusercontent.com/api-evangelist/mettle/refs/heads/main/apis.yml
name: Mettle
kind: company
description: Mettle is a digital-only business bank account brand for UK sole traders,
  freelancers, and small limited companies, wholly owned by NatWest Group and
  originally built with Capco. It has no physical branches and is run on separate
  technology from the core NatWest bank, offering an app-based current account with
  a UK sort code and account number, invoicing, bookkeeping, tax tools, and a free
  FreeAgent accounting integration. As a NatWest Group brand, Mettle participates in
  UK Open Banking through NatWest Group's "Bank of APIs" developer platform,
  publishing PSD2 / OBIE-conformant APIs - a public, unsecured Open Data (Product)
  API describing its business current accounts, plus the FAPI-secured Read/Write
  family (Account & Transaction Information, Payment Initiation, and Confirmation of
  Funds). Read/Write access runs against a live production gateway
  (api.openbanking.prd-mettle.co.uk) secured with OAuth2/OIDC, mutual-TLS client
  authentication, and PSD2 strong customer authentication using OBIE/eIDAS
  certificates, onboarded via the Bank of APIs portal. Mettle is delivered under
  NatWest Group's FCA-authorised banking group and is a challenger/digital
  proposition rather than one of the CMA9 mandated brands.
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-23'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
tags:
- Financial Services
- Banking
- Business Banking
- Open Banking
- PSD2
- OBIE
- FAPI
- United Kingdom
- Payments
- Account Information
- Challenger Bank
- Fintech
created: '2026-07-23'
modified: '2026-07-23'
specificationVersion: '0.21'
apis:
- aid: mettle:mettle-open-data-product-api
  name: Mettle Open Data Product API
  description: Mettle's public, unsecured UK Open Banking Open Data (Product) API,
    exposing reference information about the business current accounts Mettle offers
    to sole traders and limited companies. Conforms to the OBIE Open Data API
    standard; no credentials required to read.
  humanURL: https://www.bankofapis.com/products/natwest-group-open-banking/products-and-locations/documentation/mettle
  baseURL: https://api.openbanking.prd-mettle.co.uk/open-banking/v2.3
  tags:
  - Open Data
  - Business Current Accounts
  - Products
  properties:
  - type: OpenAPI
    url: openapi/mettle-open-data-api-openapi.json
  - type: Documentation
    url: https://www.bankofapis.com/products/natwest-group-open-banking/products-and-locations/documentation/mettle
  - type: APIReference
    url: https://www.bankofapis.com/products/natwest-group-open-banking/products-and-locations/documentation/mettle
- aid: mettle:mettle-account-transaction-api
  name: Mettle Account and Transaction API
  description: OBIE Read/Write Account & Transaction Information (AIS) API for Mettle
    business current accounts, exposing accounts, balances, transactions, and related
    resources to FCA-authorised third parties. FAPI-secured with OAuth2/OIDC, mTLS,
    and PSD2 strong customer authentication.
  humanURL: https://www.bankofapis.com/products/accounts/documentation/mettle
  baseURL: https://api.openbanking.prd-mettle.co.uk/open-banking/v3.1/aisp
  tags:
  - Account Information
  - Transactions
  - AIS
  properties:
  - type: Documentation
    url: https://www.bankofapis.com/products/accounts/documentation/mettle
  - type: APIReference
    url: https://www.bankofapis.com/products/accounts/documentation/mettle
- aid: mettle:mettle-payment-initiation-api
  name: Mettle Payment Initiation API
  description: OBIE Read/Write Payment Initiation Services (PIS) API for Mettle,
    allowing FCA-authorised third parties to initiate domestic and other payments
    from a customer's Mettle account with their consent. FAPI-secured with
    OAuth2/OIDC, mTLS, and PSD2 strong customer authentication.
  humanURL: https://www.bankofapis.com/products/payments/documentation/mettle
  baseURL: https://api.openbanking.prd-mettle.co.uk/open-banking/v3.1/pisp
  tags:
  - Payment Initiation
  - Payments
  - PIS
  properties:
  - type: Documentation
    url: https://www.bankofapis.com/products/payments/documentation/mettle
  - type: APIReference
    url: https://www.bankofapis.com/products/payments/documentation/mettle
- aid: mettle:mettle-confirmation-of-funds-api
  name: Mettle Confirmation of Funds API
  description: OBIE Read/Write Confirmation of Funds (CBPII) API for Mettle, letting
    card-based payment instrument issuers confirm whether funds are available on a
    customer's Mettle account. FAPI-secured with OAuth2/OIDC, mTLS, and PSD2 strong
    customer authentication.
  humanURL: https://www.bankofapis.com/products/card-based-payments/documentation/mettle
  baseURL: https://api.openbanking.prd-mettle.co.uk/open-banking/v3.1/cbpii
  tags:
  - Confirmation of Funds
  - CBPII
  - Funds Check
  properties:
  - type: Documentation
    url: https://www.bankofapis.com/products/card-based-payments/documentation/mettle
  - type: APIReference
    url: https://www.bankofapis.com/products/card-based-payments/documentation/mettle
common:
- type: AgenticAccess
  url: agentic-access/mettle-agentic-access.yml
- type: DomainSecurity
  url: security/mettle-domain-security.yml
- type: Authentication
  url: authentication/mettle-authentication.yml
- type: OAuthScopes
  url: scopes/mettle-scopes.yml
- type: Conformance
  url: conformance/mettle-conformance.yml
- type: Compliance
  url: https://www.bankofapis.com/products/natwest-group-open-banking
- type: Conventions
  url: conventions/mettle-conventions.yml
- type: Idempotency
  url: conventions/mettle-conventions.yml
- type: ErrorCatalog
  url: errors/mettle-problem-types.yml
- type: Lifecycle
  url: lifecycle/mettle-lifecycle.yml
- type: Deprecation
  url: https://www.bankofapis.com/products/natwest-group-open-banking
- type: DataModel
  url: data-model/mettle-data-model.yml
- type: WellKnown
  url: well-known/mettle-well-known.yml
- type: MCPServer
  url: mcp/mettle-mcp.yml
- type: LLMsTxt
  url: llms/mettle-llms.txt
- type: Overlay
  url: overlays/mettle-open-data-api-overlay.yaml
- type: Sandbox
  url: https://developer.sandbox.natwest.com/
- type: AgentSkill
  url: skills/_index.yml
- type: Website
  url: https://www.mettle.co.uk/
- type: DeveloperPortal
  url: https://www.bankofapis.com/
- type: Documentation
  url: https://www.bankofapis.com/products/natwest-group-open-banking/products-and-locations/documentation/mettle
- type: StatusPage
  url: https://www.bankofapis.com/performance/service-interruptions
- type: Blog
  url: https://www.mettle.co.uk/blog/
- type: LinkedIn
  url: https://www.linkedin.com/company/join-mettle
- type: Support
  url: https://www.mettle.co.uk/contact-us/
- type: TermsOfService
  url: https://www.mettle.co.uk/docs/terms-and-conditions/1.5.pdf
- type: PrivacyPolicy
  url: https://www.mettle.co.uk/privacy-notice/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com