# Set Validity Periods

Sets date/time ranges when a promotion is valid. If the promotion is read-only (read_only = true), you cannot edit existing periods, but you can add new ones.

  NoticeThis API call does not contain the project_id path-parameter, so you need to use the API key that is valid in all the company’s projects to set up authorization.

Endpoint: PUT /merchants/{merchant_id}/promotions/{promotion_id}/periods
Version: 2.0
Security: basicAuth

## Path parameters:

  - `merchant_id` (integer, required)
    Merchant ID.

  - `promotion_id` (integer, required)
    Promotion ID.

## Request fields (application/json):

  - `periods` (array)
    Date/time ranges.

  - `periods.from` (string)
    Period start.

  - `periods.offset` (string)
    Number of the element from which the list is generated (the count starts from 0).

  - `periods.to` (string)
    Period end.


## Response 204 fields