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This reference is key for your comprehensive understanding of Commerce and, as such, essential for the successful use of our payment orchestration products. Commerce APIs make use of RESTful conventions when possible and where it makes sense. All calls use the standard HTTP verbs to express access semantics, like GET, POST, PATCH, and DELETE. Other related conventions for our API can be found in the section below.
Gated EndpointsLabeled with:Gated FeatureSome of the features offered by Commerce are gated and require explicit activation. In order to get access you need to contact your account manager.
Beta EndpointsLabeled with:Beta FeatureCommerce offers various features as part of our beta release track. These features are experimental and subject to change or removal at any time. They may also have limited support and stability.By default, accounts do not have access to beta features unless explicitly subscribed to beta releases. If you would like to enable beta features, please contact your account manager for subscription options.

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JSON Conventions

  • Resources are addressable by a UUIDv4 id property.
  • Property names are always in snake_case.
  • Commerce does not support empty strings. To unset a string value, use an explicit null value instead.
  • Temporal data is encoded in ISO 8601 strings.

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Authentication

Commerce supports API keys to authenticate requests. The keys are passed in via the HTTP header x-api-key. 
curl --header 'X-API-Key: <SECRET>' \
  --request POST 'https://api.hellgate.io/...'
The keys must be handled with care and kept secure. Never hardcode the API keys in your source code, but keep them solely on your backend systems.

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API Use

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API Versions

Commerce API will be updated regularly, to include new features and updates to existing ones. We package these changes into versions that can be addressed using a header field (x-hellgate-version). If there is no version specified in the header, the most recent version is being used. 
curl --header 'x-hellgate-version: <SELECTED VERSION>' \
  --request POST 'https://api.hellgate.io/...'
Commerce sets the x-hellgate-version header on API responses, to tell the integrator which version is in use.

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Idempotency

To prevent your system from handling requests twice and thus, for example, charging a customer twice, Commerce supports idempotency on requests to the API. The behavior is controlled via the header field x-idempotency-Key. 
curl --header 'x-idempotency-key: <key>' ...

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Pagination

Endpoints that return lists of objects support cursor-based pagination requests. By default, Commerce returns up to 50 objects per API call. If the number of objects in a response from a support endpoint exceeds the default, then an integration can use pagination to request a specific set of the results and/or to limit the number of returned objects. If an endpoint supports pagination, the response body follows this structure:
Response Sample
{
  "current_page": 1,
  "page_size": 50,
  "total_items": 200,
  "total_pages": 4,
  "data": [...]
}
The single pages can be requested with query parameters:
ParameterTypeDescription
limitintegerThe maximum amount of objects to be returned on a page.
pageintegerThe requested number of the page to return.

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Request Errors

Commerce uses the standard errors to indicate the client errors on the gateway level.
The response payload for processing errors follows a standard format.
{
  "status": "the HTTP status code",
  "classifier": "the classifier of the error",
  "message": "interesting for humans..."
}

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Business Errors

The processing errors refer to the primary functions of Commerce and not necessarily to the related business logic. For example, a failed authorization due to insufficient funds will result in a 200 response, as the payment layer could successfully process the request (even though the business result is negative).