jiff

docs.rs: https://docs.rs/jiff

crates: https://crates.io/crates/jiff

The jiff crate has a super excellent API that is very ergonomic to use and ry provides a nearly complete wrapper around it.

A good amount of time, and a greater amount of thought has gone into balancing the jiff python api to be both ergonomic and performant.

python-conversions

The structs under ryo3-jiff are convertable to/from python’s datetime.* types and the conversions are pretty well tested (ty hypothesis).

pyo3-v0.24.0 & jiff-02

The conversions to/from python datetime.* types were originally hand rolled ( by me (jesse)) using the ‘new-type’ pattern, HOWEVER pyo3-v0.24.0 provides conversions via the jiff-02 feature flag, which is what is used now.

ry-v0.0.37 will be the last version with the mostly hand rolled conversions.

ry-v0.0.38 will be the first version with the jiff-02 feature flag.

As of 2025-03-12 pyo3 does not seem to support converting Span -> datetime.timedelta, so that is still hand rolled.

ry vs whenever

There is another library called whenever that provides a similar datetime library to that of ryo3-jiff (both jiff and whenever are based on the temporal API).

No formal benchmarks between ry and whenever have been done, but I have copy-pasta-ed some of the benchmarks from the whenever repo and translated them to ry and the results were pretty similar; whenever is faster for some things, ry is faster for others, but both are wildly more performant than python’s built in datetime module and pendulum – differences in performance are almost all measured in nanoseconds.

Big shoutout to “Mr. Dutch Airlines” guy (@ariebovenberg) who wrote whenever! Love the name of the library too!