Is code injection via api possible?

Site URL: https://dragonfly-fennel-r5xx.squarespace.com/config/

Hi I'm brand new to squarespace and trying to edit my wife's website.
I'm a developer and editing 7.1 is a huge pain. The main reason is that I cannot simply add custom classes and ids.

I've written scripts and included them in the footer to inject classes and ids but a better solution would be to be able to do this via an api.

Would it be possible to inject scripts in my website via the api instead of the editor panel?

Thank you.

The developer platform is only available in 7.0.

What do you need to add classes to? Sometimes there are other workarounds.

33 minutes ago, rwp said:

The developer platform is only available in 7.0.

What do you need to add classes to? Sometimes there are other workarounds.

Wow that's really....Unfortunate. 

I need to add classes to everything/anything as there are a lot of customizations to be done. Using complicated selectors is really not fun. And I want to be able to do this easily for future sites

I might just host a custom script on my own server and include it in the head.