generated: '2026-07-23'
method: searched
source: >-
  OBIE Read/Write API standard + OBIE Open Data API standard v1.3
  (openapi/obie-open-data-api-standard-v1.3-swagger.json). Metro Bank's Open
  Banking APIs conform to these cross-cutting conventions.
docs: https://developer.metrobankonline.co.uk/Overview
authentication:
  open_data: public (no auth)
  read_write: FAPI OAuth2/OIDC + mutual TLS + PSD2 SCA
  ref: authentication/metro-bank-authentication.yml
idempotency:
  supported: true
  scope: Payment Initiation (PIS) write operations
  header: x-idempotency-key
  max_length: 40
  retention: >-
    OBIE standard - idempotent replay of a payment/consent POST with the same
    x-idempotency-key and identical payload returns the original resource rather
    than creating a duplicate.
  note: >-
    Idempotency is an OBIE Read/Write requirement for payment-initiation POSTs;
    the unauthenticated Open Data GET/HEAD surface is naturally idempotent.
tracing:
  request_id_header: x-fapi-interaction-id
  note: >-
    FAPI interaction id echoed on request and response for end-to-end
    correlation; x-fapi-auth-date, x-fapi-customer-ip-address and
    x-customer-user-agent convey customer-context on Read/Write calls.
pagination:
  style: cursor-links
  response_fields:
    - Links.Self
    - Links.First
    - Links.Prev
    - Links.Next
    - Links.Last
    - Meta.TotalPages
  open_data:
    envelope_fields: [meta.LastUpdated, meta.TotalResults, meta.Agreement]
    note: >-
      Open Data list responses carry a meta block (LastUpdated, TotalResults,
      Agreement); Read/Write list responses use OBIE Links/Meta paging.
conditional_requests:
  supported: true
  request_headers: [If-Modified-Since, If-None-Match]
  response_headers: [ETag, Last-Modified]
  note: Open Data GETs support conditional requests (304 Not Modified) via ETag.
content_negotiation:
  open_data_media_type: application/prs.openbanking.opendata.v1.3+json
  read_write_media_type: application/json
versioning:
  scheme: uri-path
  examples: [/open-banking/v2.3 (Open Data), /open-banking/v3.1 (Read/Write)]
  ref: lifecycle/metro-bank-lifecycle.yml
error_envelope:
  open_data: standard HTTP status codes (400/408/429/500/503) with a plain error body
  read_write: OBIE error structure (Code, Id, Message, Errors[] with ErrorCode/Message/Path)
  ref: errors/metro-bank-problem-types.yml
rate_limiting:
  signalled: true
  status: 429 Too Many Requests
  note: >-
    Open Data responds 429 "You have requested this resource too often. Slow
    down."; Read/Write enforces per-TPP throttling per the OBIE operational
    guidelines.