C# implementation of "Securing Webhooks" sample code https://documentation.mailgun.com/user_manual.html#webhooks

MailgunUtil.cs

using System;
using System.Text;
using System.Security.Cryptography;

class MailgunUtil
{    
    /// <summary>
    /// Authenticates incoming requests to a Mailgun webhook (https://documentation.mailgun.com/user_manual.html#webhooks).
    /// </summary>
    /// <example>
    /// <code>bool verified = MailgunUtil.Verify(API_KEY, Request.Form["token"], Request.Form["timestamp"], Request.Form["signature"])</code>
    /// </example>
    public static bool Verify(string apikey, string token, string timestamp, string signature)
    {
        var hmac = new HMACSHA256(Encoding.ASCII.GetBytes(apikey));
        var sigBytes = hmac.ComputeHash(Encoding.ASCII.GetBytes(timestamp + token));
        string sigString = BitConverter.ToString(sigBytes).Replace("-", "");
        return signature.Equals(sigString, StringComparison.OrdinalIgnoreCase);
    }
}

I was having trouble implementing this and your snippet worked great, thanks.

Useful little Gist, thanks.

Thanks! That was helpful

Thank you so much, sir!!!!