@Nemo157 after manually testing, I saw one thing:

we do seem to follow semver logic, so a request to /crate/itertools/0.10.0/status.json, where 0.10.0 doesn't exist, would lead to the endpoint returning the status for 0.10.5 (the latest semver for this).

Seeing the two use-cases I can imagine:

1. shields.io will request /latest/ (?)
2. crates.io will request a specific version

Perhaps I'm missing another case?

for the crates.io case I could imagine some edge-cases where the status for a version would be returned that crates.io didn't request. Though this could currently only happen when we're missing a version that is not the latest of that semver bracket.

Would crates.io check the returned version? Or should we perhaps return a redirect similar to the builds.json endpoint? ( crates.io would need to ignore that one too then).

Huh, interesting, likely the only reason that crates.io doesn't make that mistake right now is that the redirect is lacking a CORS header. Testing on https://crates.io/crates/stylish-core/0.1.0 (which isn't on docs.rs because of weird reasons around cyclic dependencies, but 0.1.1 is):

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://docs.rs/crate/stylish-core/0.1.0/builds.json. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). Status code: 302.

I could make it only support exact or latest, and return an error on semver matches still, or when changing crates.io to use this endpoint make it do a request to /={version}/.

I could make it only support exact or latest, and return an error on semver matches still, or when changing crates.io to use this endpoint make it do a request to /={version}/.

Sleeping over it, expecting the latter sounds like a valid approach.

That means the only remaining question (for me, right now) seems to be:

so we want consistency with the other pages, and the builds.json endpoint? Because in these, we have redirects for semver matches.

@kornelski given lib.rs' source has gone private, would you be able to migrate to this new API? https://docs.rs/crate/{crate}/{version}/status.json returning a simple { doc_status: boolean, version: string } response. (The version parameter can be a semver matcher, if you want to do exact versioning like I'm recommending for crates.io you should use ={version}, but since you don't have per-version pages I'm not sure if that'd be the best approach).