The interaction flow is described next:

1. Upon order initiation form the customer
2. Your server asks our server for a temporary API Key at entry point api/authorization/apikey:

   Request:

   POST https://securetest.smart2pay.com/v1/authorization/apikey
   Authorization: Basic MzAyMDE6aEo1Um9iWXg5cjdGZk53Q3ZIWTlMWEhxcXIrRkV6cmM3YUp2UVFrNEdhejFtZzdSeXk=

3. Our server responds with a temporary API Key:

   Response:

   HTTP/1.1 201 Created
   Content-Type: application/json; charset=utf-8
   
   {
     "ApiKey": {
       "Value": "MzAwMDc6M2FkODVhYzctNjhlNS00MTA2LTliNjctNTg3MmM1ZmI2ZDNiLTYzMzA=",
       "Created": "20181206141407",
       "LifeTime": 30,
       "AccessCounterLimit": 10,
       "Status": {
         "ID": 2,
         "Info": "Success",
         "Reasons": []
       }
     }
   }

   {"ExchangeRate":{"hint":"","regexp":"","type":"object","From":{"hint":"From currency","regexp":"^[a-zA-Z]{3}$","type":"string"},"To":{"hint":"To currency","regexp":"^[a-zA-Z]{3}$","type":"string"},"DateTime":{"hint":"Last update date and time","regexp":"","type":"datetime"},"Rate":{"hint":"Conversion rate","regexp":"","type":"float"}}}
4. The temporary API Key must be passed to the app.
5. From the app you collect the credit cards details from which you build a CardAuthenticationRequest object, together with the temporary API key obtained in the previous step. Set callback functions to handle Success and Failure cases.

   CardAuthenticationRequest cardAuthenticationRequest = new CardAuthenticationRequest("Basic " + apiKey, true);
   
   HashMap card = new HashMap();
   card.put("HolderName", ((EditText)findViewById(R.id.e_cardholder_name)).getText().toString());
   card.put("Number", ((EditText)findViewById(R.id.e_cc_number)).getText().toString());
   card.put("ExpirationMonth", ((EditText)findViewById(R.id.e_exp_month)).getText().toString());
   card.put("ExpirationYear", ((EditText)findViewById(R.id.e_exp_year)).getText().toString());
   card.put("SecurityCode", ((EditText)findViewById(R.id.e_cvv)).getText().toString());
   
   cardAuthenticationRequest.setRequestBody(CCAuthenticateRequestBodyBuilder.getBody(card));
   cardAuthenticationRequest.setCallback((new CardAuthenticationRequest.Callback() {
       public void onSuccess(@NonNull final String creditCardToken) {
           // Authorization was successful!
           // Send it to your server and initiate a transactions via REST API: https://docs-apm.nuvei.com/category/direct-card-processing/one-click-payment/
           Log.d("TokenForCreditCard", creditCardToken);
           runOnUiThread(new Runnable() {
               @Override
               public void run() {
                   displayDebugInfo("Credit Card Token:" + creditCardToken);
               }
           });
       }
   
       public void onFailure() {
           Log.w(TAG,"Card Authentication request failed.");
           runOnUiThread(new Runnable() {
               @Override
               public void run() {
                   displayDebugInfo("Card Authentication request failed.");
               }
           });
       }
   }));
   cardAuthenticationRequest.enqueue();
   

6. Our SDK calls our server with these details.
7. The server responds with a token to our SDK.
8. Our SDK passed the token back to your APP via the callback function setup in step 5.
9. The order can now be submitted from the app to your server together with the token
10. A credit card transaction using token is now initiated from your server. For more details go to: Recurring Card Payments section. You can store the token on your server for subsequent purchases.
11. Our server responds to your server with the Authorization result. Upon a successful result you can release the goods or services.
12. You pass the payment result to the app.

SDK is now fully functional in your app!