Umbraco Forms Workflow - POST to URL as JSON (with optional Bearer Access Token). Just place this file anywhere in your Umbraco+Forms project, and the dependency injection will pick it up. This will allow you to connect to Microsoft Flow or Zapier or any integration web service, from which you can send to Salesforce/Dynamics/etc.

PostToUrlAsJson.cs

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Dynamic;
using System.Net;
using System.Text.RegularExpressions;
using Umbraco.Core.Logging;
using Umbraco.Forms.Core;
using Umbraco.Forms.Core.Attributes;
using Umbraco.Forms.Core.Enums;

public class PostToUrlAsJson : WorkflowType
{
    [Setting("Url", description = "Enter the url to post to", view = "TextField")]
    public string Url
    {
        get;
        set;
    }

    [Setting("Bearer Token", description = "Optional: enter a bearer token for API access (don't include the word 'Bearer')", view = "TextField")]
    public string BearerToken
    {
        get;
        set;
    }

    public PostToUrlAsJson()
    {             
        this.Id = new Guid("eb5d0597-4964-43c4-9437-407cba35dfc6");
        this.Name = "Send form to URL as JSON object";
        this.Description = "Sends the form to a url";
        this.Icon = "icon-terminal";
        this.Group = "Services";
    }

    public override List<Exception> ValidateSettings()
    {
        List<Exception> list = new List<Exception>();
        if (string.IsNullOrEmpty(Url))
        {
            list.Add(new Exception("'Url' setting has not been set"));
        }
        return list;
    }

    public override WorkflowExecutionStatus Execute(Record record, RecordEventArgs e)
    {
        using (WebClient http = new WebClient())
        {
            http.Headers.Add(HttpRequestHeader.ContentType, "application/json");
            if (!string.IsNullOrEmpty(BearerToken))
            {
                http.Headers.Add(HttpRequestHeader.Authorization, "Bearer " + BearerToken);
                http.Encoding = System.Text.Encoding.UTF8;                
            }

            var values = new Dictionary<string, string>();
            foreach (RecordField value in record.RecordFields.Values)
            {
                values.Add(value.Field.Alias, value.ValuesAsString(true));
            }

            dynamic json = new ExpandoObject();
            json.id = record.UniqueId;
            json.formId = e.Form.Id;
            json.formName = e.Form.Name;
            json.ip = record.IP;
            json.memberKey = record.MemberKey;
            json.time = DateTime.UtcNow;
            json.values = values;
                        
            string payload = JsonConvert.SerializeObject(json);

            try
            {
                http.UploadData(Url, "POST", System.Text.Encoding.UTF8.GetBytes(payload));
                return WorkflowExecutionStatus.Completed;
            }
            catch (Exception ex)
            {
                string err = String.Format("There was a problem sending the Record with unique id '{0}' from the Form '{1}' with id '{2}' to the URL Endpoint '{3}' with the method 'POST'", record.UniqueId, e.Form.Name, e.Form.Id, Url);
                LogHelper.Error<PostToUrlAsJson>(err, ex);
                return WorkflowExecutionStatus.Failed;
            }
        }
    }
}

Updated w/great updates from MichelCollard's fork.

How do I get the Bearer Token to pass in? We are using an OAuth workflow for login. I need to pass the logged in user's token so the API can authenticate and extract the userId from the token.

I tried passing in an invalid URL and still got the thank you message. Does not appear the try catch around the post worked?

When you say "Just place this file anywhere in your Umbraco+Forms project," can you give me some more detail on exactly what to do with the .cs file that I have saved this code to?

Ensure you have included it in your VS project file, or maybe add it to the app_code folder if you're not recompiling?