Welcome Back

Even if your POS is in an old or proprietary language (Clarion, Clipper, SAP, PowerBuilder), you can invoke this one-line command from your software:

curl -X POST "https://www.whocallme.online/api" \
  -H "x-api-key: " \
  -F "number=923001234567" \
  -F "message=Thank you for shopping! Here is your invoice." \
  -F "pdf=@C:/Invoices/INV-1092.pdf"

using System;
using System.IO;
using System.Net.Http;
using System.Threading.Tasks;

public class WhatsAppPOS {
    public static async Task SendInvoiceAsync(string phone, string pdfPath, string message) {
        using (var client = new HttpClient()) {
            client.DefaultRequestHeaders.Add("x-api-key", "");
            using (var form = new MultipartFormDataContent()) {
                form.Add(new StringContent(phone), "number");
                form.Add(new StringContent(message), "message");

                byte[] fileBytes = File.ReadAllBytes(pdfPath);
                var fileContent = new ByteArrayContent(fileBytes);
                fileContent.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/pdf");
                form.Add(fileContent, "pdf", Path.GetFileName(pdfPath));

                HttpResponseMessage response = await client.PostAsync("https://www.whocallme.online/api", form);
                Console.WriteLine(await response.Content.ReadAsStringAsync());
            }
        }
    }
}

Imports System.IO
Imports System.Net.Http

Public Class WaAgentPOS
    Public Shared Async Sub SendInvoice(phone As String, pdfPath As String, note As String)
        Using client As New HttpClient()
            client.DefaultRequestHeaders.Add("x-api-key", "")
            Using form As New MultipartFormDataContent()
                form.Add(New StringContent(phone), "number")
                form.Add(New StringContent(note), "message")
                Dim fileBytes As Byte() = File.ReadAllBytes(pdfPath)
                Dim fileContent As New ByteArrayContent(fileBytes)
                fileContent.Headers.ContentType = New Headers.MediaTypeHeaderValue("application/pdf")
                form.Add(fileContent, "pdf", Path.GetFileName(pdfPath))
                Dim response = Await client.PostAsync("https://www.whocallme.online/api", form)
            End Using
        End Using
    End Sub
End Class

import java.io.File;
import okhttp3.*;

public class WhatsAppPOS {
    public static void sendInvoice(String phone, String filePath, String note) throws Exception {
        OkHttpClient client = new OkHttpClient();
        File file = new File(filePath);

        RequestBody requestBody = new MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("number", phone)
            .addFormDataPart("message", note)
            .addFormDataPart("pdf", file.getName(),
                RequestBody.create(file, MediaType.parse("application/pdf")))
            .build();

        Request request = new Request.Builder()
            .url("https://www.whocallme.online/api")
            .addHeader("x-api-key", "")
            .post(requestBody)
            .build();

        try (Response response = client.newCall(request).execute()) {
            System.out.println(response.body().string());
        }
    }
}

const axios = require('axios');
const FormData = require('form-data');
const fs = require('fs');

async function sendInvoice(phone, filePath, note) {
    const form = new FormData();
    form.append('number', phone);
    form.append('message', note);
    form.append('pdf', fs.createReadStream(filePath));

    const response = await axios.post('https://www.whocallme.online/api', form, {
        headers: {
            ...form.getHeaders(),
            'x-api-key': ''
        }
    });
    console.log(response.data);
}

<?php
$ch = curl_init('https://www.whocallme.online/api');
$postData = [
    'number'  => '923001234567',
    'message' => 'Thank you for your purchase! Attached is your invoice.',
    'pdf'     => new CURLFile('C:\\Invoices\\INV-1092.pdf', 'application/pdf', 'INV-1092.pdf')
];
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_POST           => true,
    CURLOPT_POSTFIELDS     => $postData,
    CURLOPT_HTTPHEADER     => ['x-api-key: ']
]);
$response = curl_exec($ch);
curl_close($ch);
echo $response;
?>

import requests

url = "https://www.whocallme.online/api"
headers = {"x-api-key": ""}
data = {
    "number": "923001234567",
    "message": "Thank you for shopping! Here is your invoice."
}
files = {
    "pdf": ("INV-1092.pdf", open(r"C:\Invoices\INV-1092.pdf", "rb"), "application/pdf")
}

res = requests.post(url, headers=headers, data=data, files=files)
print(res.json())

uses
  System.Net.HttpClient, System.Net.Mime;

procedure SendInvoice(const Phone, FilePath, Note: string);
var
  Client: TNetHTTPClient;
  FormData: TMultipartFormData;
  Response: IHTTPResponse;
begin
  Client := TNetHTTPClient.Create(nil);
  FormData := TMultipartFormData.Create;
  try
    FormData.AddField('number', Phone);
    FormData.AddField('message', Note);
    FormData.AddFile('pdf', FilePath);

    Client.CustomHeaders['x-api-key'] := '';
    Response := Client.Post('https://www.whocallme.online/api', FormData);
    ShowMessage(Response.ContentAsString);
  finally
    FormData.Free;
    Client.Free;
  end;
end;

' VB6 / VBA / FoxPro: Send via Base64 JSON Payload
Dim http As Object, jsonPayload As String, b64File As String
Set http = CreateObject("MSXML2.ServerXMLHTTP.6.0")

b64File = FileToBase64("C:\Invoices\INV-1092.pdf")
jsonPayload = "{""number"":""923001234567"",""message"":""Here is your invoice."",""file_base64"":""" & b64File & """,""filename"":""INV-1092.pdf""}"

http.Open "POST", "https://www.whocallme.online/api", False
http.setRequestHeader "Content-Type", "application/json"
http.setRequestHeader "x-api-key", ""
http.Send jsonPayload

MsgBox http.responseText

' OR via 1-Line Universal Shell in VB6 / VFP:
' Shell "curl -X POST ""https://www.whocallme.online/api"" -H ""x-api-key: "" -F ""number=923001234567"" -F ""message=Invoice"" -F ""pdf=@C:\Invoices\INV-1092.pdf""", vbHide

import 'package:http/http.dart' as http;

Future<void> sendInvoice(String phone, String filePath, String note) async {
  var uri = Uri.parse('https://www.whocallme.online/api');
  var request = http.MultipartRequest('POST', uri)
    ..headers['x-api-key'] = ''
    ..fields['number'] = phone
    ..fields['message'] = note
    ..files.add(await http.MultipartFile.fromPath('pdf', filePath));

  var response = await request.send();
  var respStr = await response.stream.bytesToString();
  print('Response: $respStr');
}