Contentful is described as 'A content management system that enables cross-platform, multi-device online publishing. Businesses employ Contentful to publish editorial content for web apps, mobile apps, and, ultimately, any connected devices' and is an website in the Business & Commerce category. There are more than 25 alternatives to Contentful, not only websites but also apps for a variety of platforms, including Self-Hosted solutions, SaaS, Linux and Mac. The best alternative is WordPress, which is both free and Open Source. Other great sites and apps similar to Contentful are Strapi (Free, Open Source), Cockpit (Free, Open Source), Prismic (Freemium) and SilverStripe (Free, Open Source).
Squidex is an open source headless CMS and content management hub. In contrast to a traditional CMS Squidex provides a rich API with OData filter and Swagger definitions. It is up to you to build your UI on top of it. It can be website, a native app or just another server.
Conteidon is making it easier for people without technical skills to build and manage content and at the same time providing developers a tech friendly environment for integrating content unto multiple channels via a robust API.
More than a Headless CMS Create pages without any code change by re-using your components built in React.js You can construct a new page in minutes by mix and match existing UI Components. When you are ready, you can go live just by clicking a button.