Amazon Marketplace Web Service (MWS) API Connection Guideline

The request signature is generated using several parameters: "AWSAccessKeyId" is provided by Amazon, "SellerId" is a 14-digit unique identifier of the Amazon seller, consisting of letters and numbers, "MWSAuthToken" is a trusted developer’s token, which will be described later, "SignatureVersion" is the version of the method of receiving the signature, for example, "2", "Timestamp" is the date and time the request was sent in the format "ISO 8601", "Version" is the version of the specific API branch in the format "YYYY-MM-DD", so for the Orders API this is "2013-09-01", "SignatureMethod" is a method of obtaining a signature, for example,"HmacSHA256".

As for "SellerId" and "MWSAuthToken", here you need to take into account the specifics of Amazon to provide developers with access to seller accounts. First, you need to transfer the account to developer mode. After that, other sellers will be able to provide the newly created developer access to manage their data via the API. In the seller’s personal account, there is a list of trusted developers, each of whom is assigned a special key "MWSAuthToken", which must be provided to the developer for signing API-queries along with "SellerId". Since the seller, who has become a developer, does not need to provide access to himself, then when making queries on its own behalf, the key "MWSAuthToken" with the value "" should be specified.

Amazon does not provide sandbox-mode, and therefore all the work on the connection will be carried out according to real data. Requests signing debugging can be done under GET-requests, and if something more complicated happens, there may be a risk of breakdown. To send requests you need to use the URL https://mws.amazonaws.com/ .

After the request signature has been debugged, the API can receive some data from your personal account, for example, a list of orders. All API functionality is divided into branches by the entities, on which the work is done: Orders, Products, Fulfillment Inbound Shipments, Fulfillment Outbound Shipments, Feeds, etc. We will use OrdersAPI, http://docs.developer.amazonservices.com/en_US/orders-2013-09-01/Orders_Overview.html .

To get a list of orders, you need to use the GET-request at https://mws.amazonaws.com/Orders/2013-09-01 with the "Action" parameter with the "ListOrders" value. The "Action" parameter is used in both GET- and POST-queries, and uniquely determines the current functionality of the API. In addition, filter parameters can be specified for ListOrders, but the basic request can be made without them. So, if the request signature is debugged, when executing the request, the XML with the root element ListOrdersResponse, the first-level element ListOrdersResult and the second-level element Orders, which groups the list of Order elements, each of which is an XML API representation of the order in Amazon (Fig. 1 ), should return to the above-mentioned URL. Pagination is implemented not by any another query-parameter, but by another value of the "Action" parameter, "ListOrdersByNextToken". So, if the request for "ListOrders" returned a second-level element "NextToken", the seller has more than 100 orders. In this case, one more request with the parameters "Action" with the "ListOrdersByNextToken" value and "NextToken" with the value of "NextToken" from the last request should be made. All subsequent pagination pages are obtained through "ListOrdersByNextToken".

Each order has, for example, the string properties AmazonOrderId, PurchaseDate, OrderStatus and nested ShippingAddress, OrderTotal and others. The order information itself is quite impractical for use on the website, so to complete the picture, you need to get related products. To do this, first, make a request with "Action" with the "GetOrder" value, passing also the parameter "AmazonOrderId" with the value of the corresponding element "AmazonOrderId" from the response to the request "ListOrders" or "ListOrdersByNextToken". The response will have a list of products identified by the value of the ASIN field (Fig. 2). Data on the products themselves must be obtained from another branch, Products API, https://mws.amazonaws.com/Products/2011-10-01 , and the following parameters should be specified in the request: "Action"-"GetMatchingProduct", "ASINList. ASIN.1"- ASIN of the required product. To optimize the number of queries to API, you can specify up to 10 ASIN products, passing them respectively as parameter values "ASINList.ASIN.2", "ASINList.ASIN.3", ..., "ASINList.ASIN.10". For this branch, respectively, the "2011-10-01" value for the "Version" parameter will be used in the request signature. The structure of the response can be seen in Fig. 3.

As for the rest, it is necessary to implement error handling and integration with business logic. Also for each "Action", Amazon has its own limits on the number and frequency of queries, which, if necessary, must be monitored separately.
As well, in some queries, the "MarketplaceId" parameter, which defines the "submarket", can be passed. In addition, the market itself is determined by the domain.