Update a max bid

Updates the authenticated storefront customer's maximum (proxy) bid on an active auction item.

The customer must currently be the high bidder. The maxAmount cannot be lower than the customer's current showing bid.

If the auction item has a reserve price that has not yet been met and the maxAmount meets or exceeds it, the system will automatically place a bid at the reserve price.

post

Authorizations

AuthorizationstringRequired

Your storefront (public) token, sent as Authorization: Bearer STOREFRONT_TOKEN. Generate one in Auction Plus under Settings > API, in the Storefront API section, by clicking Generate Public Token. Required on every request.

Path parameters

idstringRequired

The auction item UID.

Example: 1c6af60by54hzdmgxy5ab4ypw0

Query parameters

fields[auction-items]stringOptional

Available values are startPrice, bidIncrementStrategy, automaticBidding, softClose, totalBids, highBidAmount, minimumBid, currentIncrement, startsAt, endsAt, position, status, enableReserve, reserveMet, processed, createdAt, updatedAt, canceledAt. You can include multiple values by separating them with a comma.

fields[variants]stringOptional

Available values are externalId, displayName, title, price, photoUrl. You can include multiple values by separating them with a comma.

fields[products]stringOptional

Available values are externalId, title, vendor, type, photoUrl, handle. You can include multiple values by separating them with a comma.

fields[bids]stringOptional

Available values are amount, submittedAt, placedAt. You can include multiple values by separating them with a comma.

fields[max-bids]stringOptional

Available values are amount, createdAt. You can include multiple values by separating them with a comma.

fields[auction-winners]stringOptional

Available values are amount, notifiedAt, paymentDueAt, paid. You can include multiple values by separating them with a comma.

viewerFieldsstringOptional

Comma-separated per-viewer fields to return under meta.viewer on the resource and any included resources. Available values: hasBid, isWatching, isHighBidder, isOwner. Requires an authenticated customer.

Example: hasBid,isWatching

includestringOptional

Comma-separated list of related resources to include in the response. Available values: variant, product, highBid, highBid.customer, viewerMaxBid, viewerWin.

Body

maxAmountnumberRequired

The new maximum bid in major currency units (e.g. 10.50).

Responses

200

AuctionItemResource

application/vnd.api+json

401

The provided user does not have access to this resource.

application/vnd.api+json

403

The provided user does not have access to this resource.

application/vnd.api+json

422

The max bid could not be updated. Inspect errors[0].code for details:

• max_bid_edit_permission_denied — the customer is not the current high bidder on the auction item.
• auction_ended — the auction has already ended.
• max_amount_below_current_bid — the new maxAmount is lower than the showing bid. meta.minimum_bid contains the showing bid amount.

application/vnd.api+json

post/auction-items/{id}/update-max-bid

POST /storefront/v1/auction-items/{id}/update-max-bid HTTP/1.1
Host: api.auctionplusapp.com
Authorization: Bearer YOUR_SECRET_TOKEN
Content-Type: application/json
Accept: */*
Content-Length: 15

{
  "maxAmount": 1
}

{
  "data": {
    "id": "4hfwg0jenx2cbf8ze3vhg0kdcr",
    "type": "auction-items",
    "attributes": {
      "startPrice": {
        "value": 100,
        "major": "1.00",
        "display": "$1.00",
        "currency": "USD"
      },
      "bidIncrementStrategy": {
        "strategy": "fixed_amount",
        "value": {
          "amount": {
            "value": 500,
            "major": "5.00",
            "display": "$5.00",
            "currency": "USD"
          }
        }
      },
      "automaticBidding": {
        "enabled": true
      },
      "softClose": {
        "enabled": false
      },
      "totalBids": 1,
      "highBidAmount": {
        "value": 5000,
        "major": "50.00",
        "display": "$50.00",
        "currency": "USD"
      },
      "minimumBid": {
        "value": 5500,
        "major": "55.00",
        "display": "$55.00",
        "currency": "USD"
      },
      "currentIncrement": {
        "value": 500,
        "major": "5.00",
        "display": "$5.00",
        "currency": "USD"
      },
      "startsAt": "2026-09-24T19:51:47.000000Z",
      "endsAt": "2026-09-24T20:51:47.000000Z",
      "position": null,
      "status": "active",
      "enableReserve": true,
      "reserveMet": true,
      "processed": false,
      "createdAt": "2026-09-24T19:51:47.000000Z",
      "updatedAt": "2026-09-24T19:51:47.000000Z",
      "canceledAt": null
    },
    "relationships": {
      "variant": {
        "data": {
          "type": "variants",
          "id": "text"
        }
      },
      "product": {
        "data": {
          "type": "products",
          "id": "text"
        }
      },
      "highBid": {
        "data": {
          "type": "bids",
          "id": "text"
        }
      },
      "viewerMaxBid": {
        "data": {
          "type": "max-bids",
          "id": "text"
        }
      },
      "viewerWin": {
        "data": {
          "type": "auction-winners",
          "id": "text"
        }
      }
    }
  }
}