Overview

Update an existing coupon's name, code, expiration, redemption limits, plan restrictions, or metadata.

What can be updated

Only the following fields can be changed after creation:

• name — display name
• code — redemption code (must remain unique within the site, alphanumeric only)
• redeem_by — expiration date (YYYY-MM-DD, must be a future date). Set to null to remove expiration
• max_redemptions — usage limit. Cannot be set lower than current redemption count
• plans — plan restrictions
• metadata — custom key-value pairs

amount_off, percent_off, duration, and currency are set at creation and cannot be changed. If passed, they are silently ignored.

Behavior

• Metadata is merged, not replaced. New keys are added to existing metadata. To clear metadata, pass an empty object.
• Plans are replaced. If plans is provided, the coupon's plan restrictions are updated to match. If plans is omitted, all existing plan restrictions are removed.