How to Integrate

Your online shop, a mobile app, or a crypto exchange may accept or send zolds to your customers, via our hosted web API. Of course, you can implement it all yourself, without the API, but we made it for you, to make your life easier. Here are the step-by-step instructions. You can also use our SDK, if your programming language is Ruby or Java. Otherwise, just work via the RESTful API and you will be fine, it’s not so difficult.

First, you create your own wallet at the WTS. You will get a keygap. Make sure you keep it safe and secure. Then, you get the API token here.

You should send this token in the X-Zold-WTS header in all HTTP requests.

Receiving Zolds

When a customer is ready to send you zolds, you create an invoice, by sending a simple HTTP request to the WTS RESTful API:

GET https://wts.zold.io/invoice.json

The JSON you get in return will look similar to this:

{ "prefix": "JjsY7sLns", "invoice": "JjsY7sLns@0123456701234567" }

Then, you generate two secret numbers: R and T (make sure they are long enough, at least 8 digits each). You keep these two numbers somewhere in your database, attached to this particular payment you are expecting from this particular customer. You ask your customer to send the payment to the invoice you just generated and mention number R in the payment details.

Then, you make an HTTP request to the Callback API:

GET /wait-for?prefix=P&regexp=R&uri=U&token=T

Here, P is the prefix from the invoice you just generated, and U is the URI where you are expecting a callback, when the payment arrives to your wallet.

When it arrives, you will get a GET HTTP request from the WTS and it will look like this:

GET /?amount=A&details=R&token=T

Here, A will be the amount of zents just arrived to your wallet, R and T will be the numbers you generated before. Using them, you can find the customer in your database and apply the incoming payment to their balance.

Your server has to respond with 200 status code and the body of the response must be OK. If this won’t happen for any reason (for example, your server is temporary down), the WTS will make another attempt to send you the GET request in a few minutes. It will keep making those attempts for 24 hours and then it will give up.

Sending Zolds

Sending is easier. You just make a single POST HTTP request, which should look like this:

POST /do-pay?bnf=W&amount=A&details=R&keygap=K&noredirect=on

Here, W is the ID of the wallet you are sending the payment to, A is the amount to send (in zents), R is some text the receiver will see in the transaction details, and K is your keygap. If the HTTP status code is not 200, something was wrong and you will see the error text right in the body of the response. If the response is 200, you should get the job ID from the X-Zold-Job HTTP header of the response.

Then, you should check the status of the job here, using J as the job ID you just received:

GET /job.json?id=J

The JSON document you will receive will look like this:

{
  "id": "sjks-8sjs-sjUJs-sjkIIL",
  "status": "OK",
  "output_length": 15362
}

If the status element of the JSON is OK, the payment has been sent. If the status is Running, it’s still in processing. In all other cases, the payment request was not successful. More details of the problem you can get at this URL:

GET /output?id=J

This request will show you the entire log of the payment request.

BTW, every time if something goes wrong, you may see the error message in the X-Zold-Error HTTP header of the response. Simply put, if this header is present, there was some error on the server.

Using Your Wallet

Aside from sending and receiving zolds you may be interested to check your wallet balance, see the list of transactions, download your private RSA key and do some other things, which are provided by the WTS API. The API is fully documented here. If you have any questions or suggestions, don’t hesitate to submit a ticket.

If something doesn’t work as expected, don’t hesitate to ask for help in our Telegram group or simply submit a GitHub ticket here.