diff --git a/lib/services/buy/simplex/simplex_api.dart b/lib/services/buy/simplex/simplex_api.dart
index bf6382fdc..cd285c706 100644
--- a/lib/services/buy/simplex/simplex_api.dart
+++ b/lib/services/buy/simplex/simplex_api.dart
@@ -174,29 +174,61 @@ class SimplexAPI {
 
   void newOrder(SimplexQuote quote) async {
     try {
-      // curl --request POST \
-      //      --url https://sandbox.test-simplexcc.com/wallet/merchant/v2/payments/partner/data \
-      //      --header 'Authorization: ApiKey XXX' \
-      //      --header 'accept: application/json' \
-      //      --header 'content-type: application/json' \
-      //      -d '{"account_details": {"app_provider_id": "pk_test_XXX", "app_version_id": "123", "app_end_user_id": "01e7a0b9-8dfc-4988-a28d-84a34e5f0a63", "signup_login": {"timestamp": "1994-11-05T08:15:30-05:00", "ip": "207.66.86.226"}}, "transaction_details": {"payment_details": {"quote_id": "3b58f4b4-ed6f-447c-b96a-ffe97d7b6803", "payment_id": "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa", "order_id": "789", "original_http_ref_url": "https://stackwallet.com/simplex", "destination_wallet": {"currency": "BTC", "address": "bc1qjvj9ca8gdsv3g58yrzrk6jycvgnjh9uj35rja2"}}}}'
-
-      // TODO launch URL which POSTs headers like https://integrations.simplex.com/docs/new-window-payment-form-submission-1
+      String version = "123"; // TODO pull from app version variable
+      String app_end_user_id =
+          "01e7a0b9-8dfc-4988-a28d-84a34e5f0a63"; // TODO generate per-user ID (pull from wallet?)
+      String signup_timestamp =
+          "1994-11-05T08:15:30-05:00"; // TODO supply real signup timestamp (pull from wallet?)
+      String referral_ip = "207.66.86.226"; // TODO update to API server IP
+      String payment_id =
+          "daaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa"; // TODO make unique and save
+      String order_id = "789"; // TODO generate unique ID per order
+      String referrer = "https://stackwallet.com/simplex"; // TODO update
+      String apiKey = "XXX";
+      String publicKey = "pk_test_XXX";
 
+      // Using simplex_api/order; doesn't work:
+      /*
       Map<String, String> headers = {
-        'Content-Type': 'application/json',
+        'Content-Type': 'application/json'
       };
       String data =
-          '{"account_details": {"app_end_user_id": "${quote.receivingAddress}"}, "transaction_details": {"digital_currency": "${quote.crypto.ticker.toUpperCase()}", "fiat_currency": "${quote.fiat.ticker.toUpperCase()}", "requested_currency": "USD", "requested_amount": ${quote.youPayFiatPrice}}}';
+          '{"account_details": {"app_end_user_id": "${app_end_user_id}"}, "transaction_details": {"payment_details": {"fiat_total_amount": {"currency": "${quote.fiat.ticker.toUpperCase()}", "amount": "${quote.youPayFiatPrice}"}, "requested_digital_amount": {"currency": "${quote.crypto.ticker.toUpperCase()}", "amount": "${quote.youReceiveCryptoAmount}"}, "destination_wallet": {"currency": "${quote.crypto.ticker.toUpperCase()}", "address": "${quote.receivingAddress}"}}';
       Uri url = Uri.parse('http://sandbox-api.stackwallet.com/order');
-
       var res = await http.post(url, headers: headers, body: data);
 
       if (res.statusCode != 200) {
         throw Exception('newOrder exception: statusCode= ${res.statusCode}');
       }
-
       final jsonArray = jsonDecode(res.body);
+      print(jsonArray);
+      */
+
+      // Calling Simplex's API manually:
+      // curl --request POST \
+      //      --url https://sandbox.test-simplexcc.com/wallet/merchant/v2/payments/partner/data \
+      //      --header 'Authorization: ApiKey $apiKey' \
+      //      --header 'accept: application/json' \
+      //      --header 'content-type: application/json' \
+      //      -d '{"account_details": {"app_provider_id": "$publicKey", "app_version_id": "123", "app_end_user_id": "01e7a0b9-8dfc-4988-a28d-84a34e5f0a63", "signup_login": {"timestamp": "1994-11-05T08:15:30-05:00", "ip": "207.66.86.226"}}, "transaction_details": {"payment_details": {"quote_id": "3b58f4b4-ed6f-447c-b96a-ffe97d7b6803", "payment_id": "baaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa", "order_id": "789", "original_http_ref_url": "https://stackwallet.com/simplex", "destination_wallet": {"currency": "BTC", "address": "bc1qjvj9ca8gdsv3g58yrzrk6jycvgnjh9uj35rja2"}}}}'
+
+      Map<String, String> headers = {
+        'Content-Type': 'application/json',
+        'Accept': 'application/json',
+        'Authorization': 'ApiKey ${apiKey}',
+      };
+      String data =
+          '{"account_details": {"app_provider_id": "$publicKey", "app_version_id": "$version", "app_end_user_id": "$app_end_user_id", "signup_login": {"timestamp": "$signup_timestamp", "ip": "$referral_ip"}}, "transaction_details": {"payment_details": {"quote_id": "${quote.purchaseId}", "payment_id": "$payment_id", "order_id": "$order_id", "original_http_ref_url": "$referrer", "destination_wallet": {"currency": "${quote.crypto.ticker.toUpperCase()}", "address": "${quote.receivingAddress}"}}}}';
+      Uri url = Uri.parse(
+          'https://sandbox.test-simplexcc.com/wallet/merchant/v2/payments/partner/data');
+      var res = await http.post(url, headers: headers, body: data);
+
+      if (res.statusCode != 200) {
+        throw Exception('newOrder exception: statusCode= ${res.statusCode}');
+      }
+      final jsonArray = jsonDecode(res.body);
+      print(jsonArray);
+      // TODO check if {is_key_required: true} (indicates success)
 
       return;
     } catch (e, s) {