In the past I have found and shared online resources for developers (e.g. playcode.io), and today I have another one!
htmleditor.io does basically what the URL suggests – it allows you to edit HTML. But it does it all in your browser. And it renders the changes in real time.
This is a very handy tool if you’re making subtle changes to a static page, or working with content for an email template.
I hope it helps!