History
Let's start with a bit of history. Neos originated from TYPO3. TYPO3 is just like Neos an open source content management system (also called CMS) based on PHP and developed by the TYPO3 Association. Open source means that the source code is freely available and can be used by anyone for free. Typical for both TYPO3 and Neos CMS is that it is community driven open source. This means that there is not a party behind it with commercial considerations but an entire community (consisting of volunteers and digital agencies).
In 2015, the community members who developed the new version of TYPO3 called "TYPO3 Neos" announced that TYPO3 Neos continues independently as Neos CMS. The official reason: after a long and difficult development period, two products were created, with their own focus. TYPO3 CMS takes the classic separation of frontend and backend as a starting point, while Neos CMS focuses on an innovative concept with the goal of promoting ease of use for web editors. This was not compatible in one system. In the end, both parties felt that it was better to separate the development of the two systems, so as to no longer interfere with the process and each other.
The difference between TYPO3 and Neos
The biggest difference between Neos and TYPO3 CMS is the setup of the CMS. While TYPO3 maintains a strict separation between the administration interface and the front-end, Neos users see the content directly in the front-end. This makes it work very intuitively for content administrators. Administrators can click on elements and then modify them directly. Neos also works with content dimensions. All content has one or more dimensions. A dimension can be another language but personalization is also possible.