MailChimp

Setup

Going to the right URL
To make sure people end up on yourwebsite.com/emailsuccess, please do this:
In MailChimp,

1. audience

2. Manage audience

3. signup forms

4. form builder

5. forms and response emails -> confirmation thank you page

6. send subs to another URL

7. fill in something like https://yourdomain.com/emailsuccess

8. hit save

URL

Get an URL like this:

https://kjkljlkjlj.us16.list-manage.com/subscribe/post?u=211c8e286b504f8faf1b92bb2&id=74a7bddfd2
NB: with post-json instead of post, you'll get JSON in return instead.

Setup e-mail address

1. From NameCheap, nameservers to CloudFlare

2. From CloudFlare, mx records to FastMail

3. Get e-mail, verify it in MailChimp