Errors

MODIFIER_REQUIRED

A line item is missing a choice its menu requires. A modifier group on that item declares a minimum number of selections, and the cart supplied fewer — most often none at all.

Summary

Field	Value
Appears as	`errors[].code`
Response	HTTP `200` — `Order` with `isValid: false` and a populated `errors[]`
Retry unchanged	No

This is a reason code, not a top-level error code

MODIFIER_REQUIRED is an errors[].code value on the order. It is not a top-level ProblemDetail.errorCode, so it carries no HTTP status, errorCategory, or retryable field of its own. See Unified OrderError shape.

Not the same as MINIMUM_NOT_MET

These two are easy to confuse and call for opposite actions.

MODIFIER_REQUIRED — one item is missing a required choice. The fix is to pick an option for that item. Adding more items to the cart does nothing.
MINIMUM_NOT_MET — the whole order is below the store's order minimum. The fix is to add more items. Picking modifiers does nothing.

pointer tells you which one you are looking at without reading the message: MODIFIER_REQUIRED always points at a specific line item.

When This Fires

POST /v1/marketfront/orders/validate — a modifier group on a cart line item has minimumAllowed greater than the number of selections supplied, or the cart omitted a required group entirely.
POST /v1/marketfront/orders/place — the same condition at placement time, either because validation was skipped or because the commerce partner rejected the cart for a missing selection.

The catalog is the source of truth for which groups are required: read minimumAllowed on each modifierGroup of an item in the catalog set. A group with minimumAllowed: 0 is optional.

Recommended Action

Send the user back to the item's options — not to the menu, and not to the cart total.

Resolve pointer against the order body to find the offending line item.
Re-read that item's modifierGroups from the catalog set and show the groups whose minimumAllowed is not yet satisfied.
Have the user choose, then resubmit.

A blind retry will continue to fail. Validating carts client-side against minimumAllowed before you call validate avoids this error entirely, and is the recommended integration.

Example


Code
{
  "isValid": false,
  "errors": [
    {
      "code": "MODIFIER_REQUIRED",
      "message": "Please choose an option for 'Pick your size' and try again.",
      "pointer": "/cart/lineItems/0"
    }
  ]
}

ITEM_UNAVAILABLE ORDER_TOTAL_DIFFERENT

Summary

Field

Value

Appears as

errors[].code

Response

HTTP 200 — Order with isValid: false and a populated errors[]

Retry unchanged

This is a reason code, not a top-level error code

Not the same as MINIMUM_NOT_MET

These two are easy to confuse and call for opposite actions.

MODIFIER_REQUIRED — one item is missing a required choice. The fix is to pick an option for that item. Adding more items to the cart does nothing.
MINIMUM_NOT_MET — the whole order is below the store's order minimum. The fix is to add more items. Picking modifiers does nothing.

pointer tells you which one you are looking at without reading the message: MODIFIER_REQUIRED always points at a specific line item.

When This Fires

POST /v1/marketfront/orders/validate — a modifier group on a cart line item has minimumAllowed greater than the number of selections supplied, or the cart omitted a required group entirely.

POST /v1/marketfront/orders/place — the same condition at placement time, either because validation was skipped or because the commerce partner rejected the cart for a missing selection.

The catalog is the source of truth for which groups are required: read minimumAllowed on each modifierGroup of an item in the catalog set. A group with minimumAllowed: 0 is optional.

Recommended Action

Send the user back to the item's options — not to the menu, and not to the cart total.

Resolve pointer against the order body to find the offending line item.

Re-read that item's modifierGroups from the catalog set and show the groups whose minimumAllowed is not yet satisfied.

Have the user choose, then resubmit.

A blind retry will continue to fail. Validating carts client-side against minimumAllowed before you call validate avoids this error entirely, and is the recommended integration.

Code

{
  "isValid": false,
  "errors": [
    {
      "code": "MODIFIER_REQUIRED",
      "message": "Please choose an option for 'Pick your size' and try again.",
      "pointer": "/cart/lineItems/0"
    }
  ]
}