How to validate data?

[Agnostion]

How can I check on the backend side whether the received content matches the editor settings?

For example, with indents. If I set a step of 40px, then how can I check on the backend side in the right way that the user received exactly 40px in indentation? Is there some way out of the box so that I can create an editor on the back side with specific settings, load content into it and check it for compliance with the settings?

If this is not the case, then I will be glad to receive any advice or examples from your experience, thank you.

Thank you for your editor and the time spent on it, it is very valuable!

[Witoso]

How can I check on the backend side whether the received content matches the editor settings? For example, with indents. If I set a step of 40px, then how can I check on the backend side in the right way that the user received exactly 40px in indentation?

Could explain the why? It's cannot grasp the use case here. What do you mean by: the user received exactly 40px in indentation?

[Agnostion]

How can I check on the backend side whether the received content matches the editor settings? For example, with indents. If I set a step of 40px, then how can I check on the backend side in the right way that the user received exactly 40px in indentation?

Could explain the why? It's cannot grasp the use case here. What do you mean by: the user received exactly 40px in indentation?

So that one user cannot submit any styles, so that the content is within the appropriate frames, and so that other users cannot receive content outside of these frames.
After all, if I configured the editor to indent in increments of 40px, then the user can still manually send a POST request to the server and keep the indentation at, say, 100px

UPD: Sorry if I’m not good at conveying my point, but the editor literally lets you write HTML with styles. And if I want to display this content somewhere, having saved it on the server before, then I need to somehow validate this diverse content before saving it.
And since the editor already has its own validation settings (it clears content if it includes something that is not specified by settings, such as HTML tags, but I don't know what about the CSS in the style attribute), I would like to use them somehow, but on the server side.