What is lib.rs?

Lib.rs is a catalog of programs and libraries written in the Rust programming language. It has 138,506 packages, including almost all of 137,871 crates from the crates.io registry (with exceptions like spam, name squatting, etc.), plus a few notable projects published only on GitHub or GitLab. The site is unofficial, and not affiliated with the Rust Foundation.

Why use lib.rs?

Ranking algorithm

Sorting crates just by their download numbers has some downsides:

To fix these issues, lib.rs uses algorithm that uses a combination of many quality signals. The algorithm has been designed based on research for RFC 1824, feedback from Rust users, as well as inspired by Open Hub analysis, SourceRank, CocoaPods' QualityIndex, and npm search.

Crates are sorted by their overall quality score, which is a weighed combination of:

The score is combined with relevance of crate's keywords to a given category or a search query. Overall, this algorithm has proven to be very good at discovering quality crates. However, there are always edge cases. If you find poor results, please report them.

Dependency freshness

Versions are considered out of date not merely when they're less than the latest, but when more than half of users of that crate uses a newer version. This way lib.rs only warns about crates that are really lagging behind, and doesn't complain about minor / irrelevant / experimental / unupgradable versions of dependencies.

Crate pages highlight out-of-date dependency versions:

Policies

lib.rs is not a package registry itself, only a view into crates published elsewhere. Majority of the crates come from crates-io, and therefore are subject to their policies. All crates are subject to Rust's Code of Conduct.

While lib.rs shows almost all crates from crates-io, it reserves the right to omit/hide crates it deems inappropriate or were subject of a takedown request. The site disapproves of cryptocurrencies, and such crates may be downranked or hidden. Presence of crates on lib.rs is not an endorsement (they're allowed by default). Policies on data processing.

Name squatting

lib.rs disapproves of name squatting (registering crate names for purpose of holding/blocking a name, rather than to publish an actual crate). This site will downrank or hide squatted crates, and ban accounts that primarily exist to squat names. Squatting is hard to define, but here are some exceptions: