Hi, i'm developing a custom frontent with the api and i just find out that there's no method to retrieve a single post from the api with the id or another way.
if there's a way to do it please show me how.

Just use tag search with id:. E.g. id:809588.

https://yande.re/post.xml?tags=id:809588

fireattack said:
Just use tag search with id:. E.g. id:809588.

https://yande.re/post.xml?tags=id:809588

GREAT! Thanks a lot!

Another question:
How do i get total page numbers or total of posts.

IIRC, there is no way to directly get the post count with the provided API, but the post with the currently highest id can be had with: "order:id_desc limit:1".
The post id increments by one for each new post, so this gives the upper bound for the total post count.

I'd suggest consulting the sources for the details: https://github.com/moebooru/moebooru