Getting XMLHttpRequest error in Flutter Web for Razorpay API call using http post

I am getting a XMLHttpRequest error in Flutter Web for Razorpay API call using http post from past 4 days I searched on whole internet but no solution worked in my case.

Below is my Post request code using http: ^0.13.4 package:

Future<String> postRequest(String amount) async {
    var url = Uri.parse('https://api.razorpay.com/v1/orders');
    var key = 'rzp_test_Xx7Zw7hLfzozf6';
    var secret = '7PgbvLaODVzRbb9oRcaqCZMi';
    var auth = 'Basic ' + base64Encode(utf8.encode('$key:$secret'));
    print(auth);

    var body = json
        .encode({"amount": 50000, "currency": "INR", "receipt": "rcptid_11"});

    var id = DateTime.now().millisecondsSinceEpoch.remainder(100000).toString();

    var client = http.Client();
    var response = await client.post(
      url,
      headers: {
        'Content-Type': 'application/json',
        'Authorization': auth,
      },
      body: body,
    );

    print(json.decode(response.body));
    return json.decode(response.body);
  }

The Curl command:

curl  -X POST https://api.razorpay.com/v1/orders-u <YOUR_KEY_ID>:<YOUR_SECRET>-H 'content-type:application/json'-d '{    "amount": 50000,    "currency": "INR",    "receipt": "rcptid_11"}'

The complete error:

    Error: XMLHttpRequest error.
    C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/core_patch.dart 906:28                get current
packages/http/src/browser_client.dart 69:22                                                                                    <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/zone.dart 1687:54                                              runUnary
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 160:18                                        handleValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 767:44                                        handleValueCallback
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 796:13                                        _propagateToListeners       
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/future_impl.dart 593:7                                         [_complete]
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream_pipe.dart 61:11                                         _cancelAndValue
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/stream.dart 1288:7                                             <fn>
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 334:14  _checkAndCall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/operations.dart 339:39  dcall
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/html/dart2js/html_dart2js.dart 37254:58                              <fn>


    at Object.createErrorWithStack (http://localhost:62444/dart_sdk.js:5076:12)
    at Object._rethrow (http://localhost:62444/dart_sdk.js:40477:16)
    at async._AsyncCallbackEntry.new.callback (http://localhost:62444/dart_sdk.js:40473:13)
    at Object._microtaskLoop (http://localhost:62444/dart_sdk.js:40330:13)
    at _startMicrotaskLoop (http://localhost:62444/dart_sdk.js:40336:13)
    at http://localhost:62444/dart_sdk.js:35811:9

I have tried every solution over Internet but nothing worked.

This smells of a CORS error, so I just pasted your code into Dartpad, opened the Chrome console and hit run. As expected, it was a CORS error.

Next step was then to search api razorpay cors, which threw up a bunch of results all complaining about the same error (all with no solution - which doesn't bode well - typically means there isn't a solution).

Next step was to notice that no decent payment API would have you include credentials into a client side app, especially a browser app. A simple inspection of the headers in the Chrome console reveals your username/password credentials. The implication of this is that you're using the API incorrectly.

This is quickly confirmed by looking at the Razorpay website which confirms that the order api is a Server-Server api. Another clue is that all the sample code for this api is in languages like PHP, Java, Node.js, etc - i.e. for the back end.

Answer: you must not call this API from the Flutter app. It must be called from your back end.