Slugs in SEO

There are no SEO considerations for API endpoints.

Why would you need Search Engine Optimization if there is no one actually searching for those endpoints?

I am confused about using slugs in api endpoints that front end app will use it

Unless you have written a dedicated package that users must use, an api is up to the developer using it to deal with how their front end works.

You give them the instructions on how to use the api.

The site that needs any SEO would be the parent site that introduces the api and has the documentation. Not the api endpoint itself, a user isn't searching for it, they are using it.

Just a suggestion, make returned data in an api as simple and easy to use a possible.

I.e., if you can avoid a user having to loop through complex nested json do it. Make having to loop as simple as possible.

I’ve had good results pairing guest posts with outreach link building because it keeps the focus on real blogs with actual traffic. Working this way made the backlinks stick and feel way more natural. I liked that the sites were manually checked and the articles written to fit each blog, so nothing felt forced. This combo brought in steadier organic traffic for me.