> ## Documentation Index > Fetch the complete documentation index at: https://developer.hellgate.io/llms.txt > Use this file to discover all available pages before exploring further. # Register a domain > Register a domain that will present the Apple Pay button. On `self_managed` instances the domain is marked `verified` immediately: you attest domain ownership to Apple yourself by registering the domain in the Apple Developer portal, where Apple fetches the domain-association file you serve at `/.well-known/apple-developer-merchantid-domain-association.txt`. On `sf_operated` instances Guardian instead schedules a background verification that registers the domain with Apple's Web Merchant Registration API using the platform integrator identity, and the domain starts as `pending`. If the verification attempt cannot be scheduled, the request returns `503` with the classifier `ENQUEUE_FAILED`; retry the request. ## OpenAPI ````yaml /products/guardian/openapi.yaml post /api/wallet/apple-pay/domains openapi: 3.1.0 info: title: Guardian API version: '1.0' contact: name: Starfish GmbH & Co. KG email: support@hellgate.io url: https://hellgate.io/cpa/guardian license: name: Hellgate API Terms url: https://hellgate.io/terms-and-conditions servers: - url: https://{instance}.{env}.on-hellgate.cloud description: Managed instance of Guardian variables: instance: default: my-instance description: Your unique instance slug, provided during onboarding. env: default: eu1 description: Deployment environment (currently eu1). security: [] tags: - name: pci description: Management of card payment credentials under the ruling of PCI DSS. - name: network description: Management of network tokens and cryptograms for secure transactions. - name: generic description: Management of generic tokens and their schemas for various use cases. - name: metadata description: Inquiries for card metadata based on PAN, PCI tokens, or network tokens. - name: wallet description: >- Management of wallet tokens ingested from device wallets such as Google Pay. - name: apikey description: Management of API keys for service access. - name: webhook description: Management of webhooks for event notifications. - name: types description: Management of types for generic token schemas. paths: /api/wallet/apple-pay/domains: post: tags: - wallet summary: Register a domain description: > Register a domain that will present the Apple Pay button. On `self_managed` instances the domain is marked `verified` immediately: you attest domain ownership to Apple yourself by registering the domain in the Apple Developer portal, where Apple fetches the domain-association file you serve at `/.well-known/apple-developer-merchantid-domain-association.txt`. On `sf_operated` instances Guardian instead schedules a background verification that registers the domain with Apple's Web Merchant Registration API using the platform integrator identity, and the domain starts as `pending`. If the verification attempt cannot be scheduled, the request returns `503` with the classifier `ENQUEUE_FAILED`; retry the request. operationId: wallet_apple_pay_domain_register requestBody: content: application/json: schema: $ref: '#/components/schemas/apple_pay_domain_request' responses: '200': description: Success response content: application/json: schema: $ref: '#/components/schemas/apple_pay_domain' '400': $ref: '#/components/responses/400_BadRequestError' '401': $ref: '#/components/responses/401_UnauthorizedError' '403': $ref: '#/components/responses/403_ForbiddenError' '422': $ref: '#/components/responses/422_ValidationError' '503': $ref: '#/components/responses/503_ServiceUnavailableError' security: - bearerAuth: [] - APIKey: [] components: schemas: apple_pay_domain_request: type: object properties: domain: type: string description: Fully-qualified domain name. example: pay.example.com required: - domain apple_pay_domain: title: Apple Pay Domain type: object properties: id: example: 3d7f1b5a-9c4e-4f2d-b8a6-1e5c9d3b7f4a type: string format: uuid domain: type: string example: pay.example.com state: type: string example: verified enum: - pending - verified - failed last_verified_at: example: '2026-02-05T11:00:00Z' type: string format: date-time nullable: true created_at: example: '2026-02-01T09:15:00Z' type: string format: date-time required: - id - domain - state - created_at ErrorGeneric: type: object properties: code: $ref: '#/components/schemas/ErrorStatusCode' classifier: $ref: '#/components/schemas/ErrorClassifier' message: $ref: '#/components/schemas/ErrorMessage' ErrorValidation: type: object properties: code: $ref: '#/components/schemas/ErrorStatusCode' classifier: $ref: '#/components/schemas/ErrorClassifier' message: $ref: '#/components/schemas/ErrorMessage' validation_errors: type: array items: type: object properties: path: example: $.source.account_number type: string description: Json-path in the request which points to the validation error message: example: is required type: string description: Human readable validation message ErrorStatusCode: type: integer description: The corresponding HTTP status code for the error ErrorClassifier: type: string description: Technical code that helps to identify the error ErrorMessage: type: string description: Human readable representation of the error responses: 400_BadRequestError: description: Error response content: application/json: schema: $ref: '#/components/schemas/ErrorGeneric' example: code: 400 message: The request could not be handle due to invalid data classifier: BAD_REQUEST 401_UnauthorizedError: description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorGeneric' example: code: 401 message: No valid means of authentication was provided classifier: UNAUTHORIZED 403_ForbiddenError: description: Forbidden content: application/json: schema: $ref: '#/components/schemas/ErrorGeneric' example: code: 403 message: Not allowed to access this resource or feature classifier: FORBIDDEN 422_ValidationError: description: Validation error content: application/json: schema: $ref: '#/components/schemas/ErrorValidation' example: code: 422 classifier: VALIDATION_ERROR message: Validation error validation_errors: - path: json-path message: human readable error message 503_ServiceUnavailableError: description: The server is currently not able to handle the request content: application/json: schema: $ref: '#/components/schemas/ErrorGeneric' example: code: 503 message: Service unavailable classifier: SERVICE_UNAVAILABLE securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- JWT bearer token obtained via the OAuth2 client-credentials grant from the platform Authentication API. The token's scopes gate the endpoints it may call, and its audience names the Guardian instance. This is the standard way to authenticate to Guardian. APIKey: type: apiKey name: x-api-key in: header description: >- Deprecated. Long-lived instance API key, sent as `x-api-key`. Existing integrations continue to work, but new ones should use the OAuth2 bearer token instead. ````