“Regular” CMS builds the HTML at the same time it builds the dynamic content. Headless has a largely static foundation of HTML that pulls in the dynamic elements from CMS data. There is so much formatting in current era HTML, so the expensive part of a page load is the themed page. Going headless means the expensive part of the load becomes less expensive as it’s static; and the important content comes in via an AJAX call. If the calls are cheaper to perform, the server infrastructure is less taxed and potentially speedier.
More on Headless CMSes
CMSWire prepped an article with a list of Headless CMSes (https://www.cmswire.com/web-cms/13-headless-cmss-to-put-on-your-radar/).
- Butter CMS
- Contentstack
- Contentful
- dotCMS
- Mura
- Cloud CMS
- Cockpit CMS
- Core dna
- Craft CMS
- Zesty.io
- Directus
- Storyblok
- GraphQL CMS
- Gentics Mesh
- Cosmic JS
- Kentico Cloud
- Prismic.io
- Quintype
- Sanity
- Scrivito
- Squidex
- DNN Evoq Content
- Strapi
- Superdesk
You may note the CMSWirre didn’t see Drupal or WordPress as contenders for this list. In their comments section, no one saw fit to suggest either one.