[ecjhdnc2025]

Ehhh!? I don't get this at all. You obviously do both.

1) you get your input data into the form that is meaningful in the database by validating, sanitising and transforming it. Because you know what form that data should be in, and that's the only form that belongs in your database. Data isn't just output, sometimes it is processed, queried, joined upon.

2) you correctly format/transform it for output formats. Now you know what the normalised form is in the database, you likely have a simpler job to transform it for output.

It's not just lazy to suggest there's a choice here, it's wrong.

[growse]

Validating data on input is just checking for "known badness", and is pretty ineffective.

If you've got specific structure requirements for the data you store, parse it into that structure.

[ecjhdnc2025]

Right -- I would include that in "transform" in my example above.

I've seen too many forum developers spend far too much time after the fact dealing with their decision to "just use TinyMCE" ==> Oh hey, you're a server-side HTML parsing expert now anyway; wasn't that what you were trying to avoid?