Send WhatsApp

Template

{
  "from": "447700900000",
  "to": "447700900123",
  "type": "template",
  "template": {
    "name": "order_update",
    "language": "en_GB",
    "body": [
      "Sam",
      "A1042"
    ]
  },
  "reference": "order-A1042"
}

C#

// Send a WhatsApp template message with the everymessage v1 API (.NET 8 or later)
using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text;
using System.Text.Json;
using System.Text.Json.Serialization;

var apiKey = Environment.GetEnvironmentVariable("EM_API_KEY")!;
var secretKey = Environment.GetEnvironmentVariable("EM_SECRET_KEY")!;

using var http = new HttpClient { BaseAddress = new Uri("https://api.everymessage.com/") };
http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
    "Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes($"{apiKey}:{secretKey}")));

var json = new JsonSerializerOptions(JsonSerializerDefaults.Web)
{
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
};

// One recipient per call. "from" is your WhatsApp business number.
var request = new WhatsAppMessage(
    From: "447700900000",
    To: "447700900123",
    Type: "template",
    Template: new Template(
        Name: "order_update",
        Language: "en_GB",
        Body: ["Sam", "A1042"]),          // fills {{1}} and {{2}} in the approved template
    Reference: "order-A1042");

using var response = await http.PostAsJsonAsync("v1/whatsapp/messages", request, json);

// The WhatsApp API uses HTTP status codes: 202 means accepted.
// 409 means the template isn't approved, or a free-form message is outside the 24-hour window.
if (!response.IsSuccessStatusCode)
    throw new InvalidOperationException(
        $"WhatsApp send failed ({(int)response.StatusCode}): {await response.Content.ReadAsStringAsync()}");

var result = await response.Content.ReadFromJsonAsync<SendResult>(json)
             ?? throw new InvalidOperationException("Empty response from everymessage");

Console.WriteLine($"{result.To}: {result.Status} (message {result.MessageId}, {result.Category}, charged {result.Charged})");

record WhatsAppMessage(string From, string To, string Type, Template? Template = null,
    TextBody? Text = null, string? Reference = null);
record Template(string Name, string Language, IReadOnlyList<string>? Body = null);
record TextBody(string Body);

record SendResult(string Status, string To, string Type, string? Category, long? MessageId, decimal Charged);

C#

// List your approved WhatsApp templates with the everymessage v1 API (.NET 8 or later)
using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text;

var apiKey = Environment.GetEnvironmentVariable("EM_API_KEY")!;
var secretKey = Environment.GetEnvironmentVariable("EM_SECRET_KEY")!;

using var http = new HttpClient { BaseAddress = new Uri("https://api.everymessage.com/") };
http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
    "Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes($"{apiKey}:{secretKey}")));

using var response = await http.GetAsync("v1/whatsapp/templates?status=APPROVED");
if (!response.IsSuccessStatusCode)
    throw new InvalidOperationException(
        $"List failed ({(int)response.StatusCode}): {await response.Content.ReadAsStringAsync()}");

var result = await response.Content.ReadFromJsonAsync<TemplateList>()
             ?? throw new InvalidOperationException("Empty response from everymessage");

foreach (var t in result.Templates)
    Console.WriteLine($"{t.Name} ({t.Language}, {t.Category}): {t.BodyParamCount} body parameter(s)" +
        (t.HeaderFormat is null ? "" : $", {t.HeaderFormat} header"));

record TemplateList(IReadOnlyList<TemplateInfo> Templates);
record TemplateInfo(string Name, string Language, string Category, string Status,
    int BodyParamCount, string? HeaderFormat, int ButtonCount);