Set the customer's birthday

POST /customers/{customer_id}/birthday


Scope	`customers:write`
Customer session token	Accepted with the `write` scope, for the token’s own customer
Rate limit class	`write` (limits)
Idempotency key	Required (idempotency)
MCP tool	`charm_set_customer_birthday`

As the widget’s birthday form: the birth year is required when the program asks for it, and a birthday can be changed once a year (reason: change_locked). The birthday reward is issued by the birthday rule, not by this call.

Parameters

Name	In	Type	Description
`customer_id`	path	string	Shopify customer GID (percent-encoded, e.g. `gid%3A%2F%2Fshopify%2FCustomer%2F123`) or the numeric customer id.

Request body

Field	Type	Description
`month`	integer
`day`	integer
`year`	integer	(optional)
`locale`	string	(optional)

Response `200`

Returns BirthdayResult.

Field	Type	Description
`changed`	boolean
`birthday`	object or null	(nullable)

{
  "changed": true,
  "birthday": {
    "month": 1,
    "day": 1,
    "year": 1
  }
}

Example

curl -X POST "https://charm.appfleece.app/api/v1/customers/7712345/birthday" \
  -H "Authorization: Bearer chrm_live_..." \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{"month":1,"day":1}'

Errors

unauthorized · invalid_token · token_expired · insufficient_scope · access_required · not_found · validation_error · rate_limited · idempotency_conflict

Every error body carries code, message, request_id and a doc_url pointing at the matching entry in the error catalog.