Boomla is an actually free website builder and application platform. All for free:

create a website in the browser without code use your own domain no branding or ads injected start with a beautiful template drag-and-drop user interface hosting is included clone your website for editing unlimited websites comes with unlimited bandwidth and visitors version history worldwide CDN - content delivery network integrate 3rd party services 1 GB storage which is plenty for a website

For developers (also free):

fully programmable on the server (that's unusual) write custom applications for yourself and others browser based IDE built-in Turbo CSS support use the Turbo UI component library built-in user management