Sitecore Forms: Redirecting to External URL

I came across a scenario where I need to redirect to a external url(thank you page) after form submission. It’s achievable using formSubmitContext’s RedirectUrl property on your Custom Submit Action.

Here is the code snippet – 

protected override bool Execute(string data, FormSubmitContext formSubmitContext)
		{
//Prepare model
//WebApi Call

//Redirect to external URL
var thankYouPageUrl = $"{HttpContext.Current.Request.Url?.Scheme}://{HttpContext.Current.Request.Url?.Host}/[thank-you-page-path]/";

formSubmitContext.RedirectUrl = $"{thankYouPageUrl}?id={add-any-querystring-if-needed}";
formSubmitContext.RedirectOnSuccess = true;              
return true;

}

Hope this helps someone. Happy Sitecoring!