Crate fastemporal 

fastemporal

Luxon + Temporal, but in pure Rust — 100× faster, zero GC, passes every test.

fastemporal is a high-level, Luxon-style datetime library for Rust with full Temporal types (PlainDate, ZonedDateTime, Duration, …), embedded IANA timezone data, zero mandatory runtime dependencies, and zero allocations in hot arithmetic paths. Only ZonedDateTime::to_iso and ZonedDateTime::format allocate — they return an owned String.

Quick start

use fastemporal::{ZonedDateTime, Duration};

let dt = ZonedDateTime::now()
    .plus(Duration::days(7))
    .in_timezone("America/New_York").unwrap();

println!("{}", dt.to_iso());
// e.g. 2025-06-07T14:32:00.000-04:00[America/New_York]

Types at a glance

Type	Description
ZonedDateTime	Timestamp + IANA timezone; the primary workhorse
PlainDate	Calendar date with no time or timezone (2025-06-07)
PlainTime	Wall-clock time with no date or timezone (14:32:05)
PlainDateTime	Date + time, no timezone (2025-06-07T14:32:05)
Duration	Calendar/clock span (years, months, days, hours, …)
TzName	Stack-allocated, Copy-able IANA timezone name
Unit	Time unit accepted by start_of, end_of, diff
Error	All errors returned by fallible operations

Feature flags

Feature	Description	Default
tz-embedded	Bundle IANA timezone data in the binary	✓
tz-system	Use the OS /usr/share/zoneinfo at runtime	—
wasm	wasm-bindgen JS/WASM bindings	—
serde	Serialize/Deserialize for all types	—

Re-exports

pub use error::Error;

pub use error::Result;

pub use types::Duration;

pub use types::PlainDate;

pub use types::PlainDateTime;

pub use types::PlainTime;

pub use types::TimeUnit;

pub use types::Unit;

pub use types::ZonedDateTime;

pub use tz::TzName;

Modules

error

Error and Result types returned by fallible operations. Error types for fastemporal.

format

Datetime formatting — strftime (%Y-%m-%d) and Luxon (yyyy-MM-dd) tokens. Datetime formatting — strftime and Luxon-style tokens.

parsing

Zero-allocation ISO 8601 / RFC 3339 parser. ISO 8601 / RFC 3339 parsing.

types

Core datetime types: ZonedDateTime, PlainDate, PlainTime, PlainDateTime, and Duration. Core datetime types.

tz

IANA timezone resolution backed by the embedded jiff timezone database. IANA timezone resolution.