Of all the content management systems out there, contentful seems to be the most flexible. It consist of an user interface with an API a front end app can retrieve data from.

It makes no assumptions about how your data is presented or structured, and you can form any kind of content in the interface. Architectural portfolio with square footage attributes? Check. Carousel section on a page? Check. A blog? No problem. Entire landing pages consisting of sections that have child items in them and attributes for each child? Not an issue. Image hosting / cdn and resizing? No problem. Character limits? Widely supported. Multilingual? Easy peasy

There are two parts of the interface. Content types and content items. Content types is just a definition of how a content item is structured, you can add fields such as title, unique id, image, rich text, lists of child content items, etc. And then the API will just return a list of content items in JSON array or object format.

There is service integration with common apps, or data sources.

Because it’s just an API call, you can use literally any tech stack with it. It won’t stop you from using MySQL or any other technology alongside it. No messing about compilation, Java, maven, like with AEM. No being constrained to the CMS’s programming language or hosting environment like with Wordpress (to an extent, wp has an API too). You can integrate it with any app, whether it be serverless, on a vm, or inside a docker container.

Downside is the front end is really up to you. It’s just a cms for structuring your data. No preview though. How you present it is not handled by contentful. It is it’s greatest strength and not a weakness though

Hi Kamil, Have you considered Adobe Experience Manager (AEM)? It is not completely open-source but is built on top of many open source modules - like Apache Sling, Apache Felix, has a great deal of open-sourced core components, supports SPA - React and Angular Recently and can be deployed as a cloud service. Good luck in your search!

I'd like to share my experience for a similar use case.

A couple of months back I was in a similar place while facing some similar set of challenges within our SEO and Content Team. We were working with WordPress at that moment and for some parts - we still do. While WordPress is a very fast, intuitive and comprehensive tool to power static pages, it's not ideal for: 1. The content team as it requires some level of technical skills 2. Code reusability perspective - impacts performance in a longer run 3. Performance and user experience can easily go for a toss considering content team may not be diligent with everything outside the scope of the content

While evaluating we were looking at these key criterias: 1. SEO, Performance and UX 2. Ease of use for Content Team, developer independence 3. Learning Curve for devs and more importantly content creators 4. Support for complex design cases 5. Cost

Being part of a small org on a tight budget our natural inclination was for open-source solution, Strapi, and so we gave it a go for a smaller project before jumping the marketing wagon.

Strapi is a great tool, easy to learn and pick up. You get most of the design use cases out of the box baked for you. It's a Node.js service so you'll need to manage the service (meaning you'll have to handle monitoring, logging, cdn, auth, etc) and DB - which requires quiet some dev bandwidth. Now Strapi is still very young in term of DB migrations (not a seamless deployment yet - no schema diffing mechanism), setting up different environments required effort and you can do content modeling only in development environment (the db migrations complexity) - which becomes really critical when you want devs, design and content to collaborate simultaneously and don't want repeated work for modeling. Over a 5-6 weeks of use we realised that more and more dev bandwidth is required to do progressive addition of new content and hence we did another PoC with contentful.

Comparing this with contentful - which is a managed service, comes with inbuilt environment and preview setup, gives on-the-fly content modeling (replacing all the dev bandwidth dependency for managing migrations, cdn, auth, service, etc) gives a huge advantage of speed and developer independence at a very moderate price. Plus, the UI is very intuitive (taking some concepts from Tag Manager).

Few other thing to highlight: - Both Strapi and Contentful have plugins for common tooling. - Both the dashboard supports custom data type and UI extensions. I found Contentful UI extensions much more easier to implement. - Contentful has only US based availablility zone. Simple in-memory caching can be used to improve costing and SLA.

Hope this helps!

Former Prismic.io developer here. If you want something robust vs "looks good from a distance," I would recommend Contentful. They are the biggest for a reason. Their CMS handles a lot of use cases and has great documentation. Prismic.io will work well in simple blog-esque use cases. Their more complex features break easily and their documentation is confusing. It has fallen quite a distance behind Contentful. Sanity appears to be a much newer CMS and you might come to regret the lack of features, but I've only briefly reviewed their product.