Payload CMS

Payload is a CMS that is totally focused on providing engineers with the greatest developer experience possible so they can design admin UI and APIs.

For your JavaScript application, Payload CMS is a content authoring tool. For user authentication, file uploads, internationalization, input validation, access control, programmatic hooks, and admin panel, Payload offers a turnkey solution.

Payload is made specifically to save developers time and effort when developing the backend and admin panel for websites, native applications, e-commerce, SaaS, and any other product that needs to handle the content.

Storyblok

Storyblok is also a web service, so you only need to register an account to create a project. It is more difficult to use than Contentful, but has more room for customization. In addition to the main entities, here it's possible to make auxiliary ones to use as components of the main entities. Storyblok allows grouping entities and content independently.

Also, this CMS has a unique feature. It can include your code on the frontend to see a preview of the content being created, which is important for content managers.

Of course, Storyblok has some flaws. It's not beginner-friendly, so a bit of learning is required to understand its interface. Then, it is only available in the paid version. Storyblok also has restrictions for entities, content, and files, but they are much wider than in Contentful.

Finally, Storyblok is a good CMS if you have fairly complex data structures in your project and want to fine-tune them.