External promotions
How to manage custom promotions via external services
Last updated
Getting started
How to manage custom promotions via external services
Last updated
Besides the promotion types that are supported out-of-the-box (, , , , , and ) Commerce Layer lets you integrate any kind of promotional engine as an .
When an external promotion activates — i.e. its activation rules are met — Commerce Layer triggers a POST request to the promotion_url endpoint, sending the order payload (including its line items) in the request body.
The request payload is a compliant object you can query to perform your own computation. Aside from the target resource — orders in the specific case — some relationships are also included to avoid useless API roundtrips:
market
customer
customer.tags
line_items
line_items.item
shipping_address
billing_address
Your service response (or error) must match the format described in the examples below.
The successful response must be a JSON object, returning at least the discount computed by the external logic. If needed, you can optionally enrich the response with some additional information, notification messages, and metadata:
The successful response must be a JSON object, returning at least the discount computed by the external logic to be applied to the specified line items. If needed, you can optionally enrich the response with some additional information, notification messages, and metadata:
The successful response must be a JSON object, returning at least a specific discount computed by the external logic to be applied to the specified line items. If needed, you can optionally enrich the response with some additional information, notification messages, and metadata:
If you are going to specify the discount_cents key for the single line items, make sure to do it for all of the elements of the line_items array. Keep in mind that the promotion amount is computed and distributed only for the line items whose IDs are listed in the array with a discount_cents key specified. In this case, avoid adding the discount_cents key at order the level because it's ignored if there is any line item with a specific discount_cents key set.
When you create a new external promotion, a shared secret is generated. We recommend verifying the callback authenticity by signing the payload with that shared secret and comparing the result with the callback signature header.
In case the call to your external endpoint goes timeout, responds with an internal server error, or is blocked by the open , the API keeps responding with a 200 OK status code. No promotion is added to the order and the circuit breaker internal counter (if closed) is incremented.
Be aware that specifying the line items in the response will overwrite both the associated SKU list (if any) and the options (e.g. you can distribute the discount on a purchased gift card also if the gift_card_taxable is false). In case any of the provided line item IDs is not associated with the order, no promotion is applied.
If you specify the messages key a with the related information is automatically attached to the associated order.