curl -X PATCH \
  'https://api.appcharge.com/coupons/coupon/summer26' \
  -H 'Content-Type: application/json' \
  -H 'x-publisher-token: <x-publisher-token>' \
  -d '{
    "active": false,
    "maxRedemptionsPerCustomer": null,
    "expiredBy": null,
    "startsAt": "2026-06-16T09:30:53.378Z",
    "supportedOfferExternalIds": ["1", "3"],
    "firstTimePurchase": false,
    "allowedPlayers": ["player123", "player456"]
}'

{
    "name": "summer26",
    "active": false,
    "discountPercentage": 10,
    "maxRedemptionsPerCustomer": null,
    "expiredBy": null,
    "startsAt": "2026-06-16T09:30:53.378Z",
    "supportedOfferExternalIds": ["1", "3"],
    "firstTimePurchase": false,
    "allowedPlayers": ["player123", "player456"]
}

{
    "error": "startsAt must be a time in the future."
}

{
    "error": "expiredBy must be a time later than startsAt."
}

{
    "error": "Trying to update fields that can’t be updated."
}

{
    "error": "Coupon not found."
}

{
    "error": "Unexpected error. Please contact support."
}