Please Suggest Indian Whatsapp API services

Install the Newtonsoft.Json package using NuGet in your C# project. Here see the sample code to send a WhatsApp message using Gupshup.io:

using System;
using System.Collections.Generic;
using System.Net.Http;
using Newtonsoft.Json;

namespace GupshupWhatsAppDemo
{
    class Program
    {
        static async System.Threading.Tasks.Task Main(string[] args)
        {
            // Replace with your API key and endpoint URL
            string apiKey = "YOUR_API_KEY_HERE";
            string endpointUrl = "YOUR_ENDPOINT_URL_HERE";

            // Replace with the recipient's WhatsApp number
            string toNumber = "91XXXXXXXXXX";

            // Replace with the message you want to send
            string message = "Hello from Gupshup!";

            // Create a new HTTP client and add the API key to the headers
            HttpClient client = new HttpClient();
            client.DefaultRequestHeaders.Add("apikey", apiKey);

            // Build the request content as a JSON object
            var content = new FormUrlEncodedContent(new[]
            {
                new KeyValuePair("channel", "whatsapp"),
                new KeyValuePair("src", "GUPSHUP_DEMO"),
                new KeyValuePair("dst", toNumber),
                new KeyValuePair("text", message)
            });

            // Send the POST request to the Gupshup API endpoint
            var response = await client.PostAsync(endpointUrl, content);

            // Read the response content as a string and deserialize the JSON response
            var responseContent = await response.Content.ReadAsStringAsync();
            var responseObject = JsonConvert.DeserializeObject(responseContent);

            // Output the response status and message ID
            Console.WriteLine("Response Status: " + responseObject.status);
            Console.WriteLine("Message ID: " + responseObject.message_id);
        }
    }
}