If you have no server or you implement the logic for purchase processing on the client side, you can use the following ways:

1. WebSocket API.
2. Short-polling.

Get an order status on the client side using WebSocket API

The solution uses websockets to obtain order statuses without obtaining detailed information about the order. This method is preferable: only one connection is created between the client (for example, your website or mobile application) and the Xsolla server, so there is no additional load on either the client or the server.

Complete the following steps:

1. To allow the Xsolla websocket server and your client to identify order status messages, create a connection:

const client = new Centrifuge(
connectionURL,
{
data: {
  user_external_id: user_external_id,
  auth: auth,
  project_id: project_id
}
}
)
connectionURL - wss://ws-store.xsolla.com/connection/websocket
auth - user JWT token

2. To receive new messages about order statuses, subscribe to events using the client.on function:

client.on('publication', (ctx) => {
   //handle the status
});

3. Trigger actual connection establishment:

client.connect()

4. To receive the history of changes in order statuses, connect the API history method.

client.on('subscribed', function (ctx) {
   client.history(ctx.channel, { limit: -1, since: { offset: 0 }, reverse: false }).then(function (resp) {
resp.publications.forEach((ctx) => {
   /handle the status
});

   }, function (err) {
       //handle the status
   });
});

Message body example:

{
order_id: 59614241,
status: 'new'
}

The following order statuses are possible:

• New — order was created but not paid
• Paid — order is paid
• Done — order has been delivered (all receipts sent, deliveries made on Xsolla’s side, external platforms, etc.)
• Canceled — order is canceled and payment refunded to a user

Websocket usage recommendations:

• The maximum waiting time for a response via websocket is 5 minutes.
• The connection should be established when opening the payment interface.
• The connection should be aborted once the final order status is received, either Canceled or Done.
• If the websocket’s lifespan expires or if there are any issues with the connection, use short-polling.

  Short-polling

  To get detailed information about items in the order after switching to the status, call the Get order API.

  Note

  A periodic order status poll is used — a simple HTTP request that receives the order status and information about the order. The recommended delay between requests is 3 seconds.

The XsollaCatalog.Purchase method encapsulates several methods for tracking order status. The tracking mechanism is detailed in the documentation of SDK for Unity (PC, web).

Additionally, you can implement the handling of the order status and content, which are passed to the onSuccess callback function of the purchase method.

You can track the order status using the CheckPendingOrder SDK method. Pass the following parameters to the method:

• AccessToken — the payment token, which was received when purchasing the item.
• OrderId — the order ID, which was received when purchasing the item.
• SuccessCallback — the successful payment callback.
• ErrorCallback — the request error callback.
• bIsUserInvolvedToPayment — whether the user is involved in the payment process. Pass true for purchasing with real currency, and false for free item purchasing and purchasing with virtual currency.

The tracking mechanism is detailed in the documentation of enterprise-level SDK for Unreal Engine.

To request the status and content of an order, call the CheckOrder SDK method, passing the following parameters to it:

• AccessToken — the payment token, which was received when purchasing the item.
• OrderId — the order ID, which was received when purchasing the item.
• SuccessCallback — the callback for successful order checking. The response contains the order status.
• ErrorCallback — the request error callback.