Pretty much what fxomt said. The endpoint urls are the same but on some a few parameters are different and some of the returned JSON is structured slightly differently.

When Lemmy releases 1.0 and makes big changes their API, PieFed will not be trying to make compatible changes. We’ll also be wanting to add new endpoints for PieFed-only features like feeds so the differences will increase over time.

I’ve seen a lot of people say the piefed API is similar to the lemmy api.

Indeed. In the 94-98% zone, can’t remember which exactly.

Will it become more distinct as time goes on, or do you plan on keeping them similar?

Distinct eventually. It’d be great to keep a subset of the API compatible with lemmy, but i’m not sure what rimu and andrew would think

Which version of the lemmy API is it similar to? v3 or v4?

V3