What is the simplest way to create a landing page solely for validation?

Hey we built https://versoly.com/

One of the biggest benefits is customer support. I usually respond in under a minute if I am not sleeping :)

You should be able to start collecting emails in under 10 minutes.

We're so lucky to have a lot of paid IHs using us!

I've been using https://www.landen.co/ and loving it. If you've got copy ready - it's under 10 minutes to put together a full blown landing page and you've got room for going bigger.

I've been doing landing pages myself before and thinking - oh it's just a couple of hours to put something together from a template, but it never turned out to be just that.

https://carrd.co

If its just one signup page, would recommend Dorik.com . If its lot of data that you want to display on the page and create multiple pages dynamically, check https://siteoly.com

Wordpress, Wix, Squarespace...any/all of these will work. Since you're just wanting a sign-up button, no need for any complicated forms. All of these CMS' will let you do this natively and up & running in a very short amount of time.

There are plenty of useful questions/answers on this subject on IndieHackers (for example, take a look at this post.