# BurntSushi/jiff

A datetime library for Rust that encourages you to jump into the pit of success.

Repository: https://github.com/BurntSushi/jiff
Canonical: https://ross.abutalabs.com/products/jiff
Language: Rust
License: Unlicense
License Family: permissive
Topics: calendar, civil, date, date-time, datetime, duration, iana, iso8601, jiff, local, rfc2822, rust, strftime, strptime, time, timezone, tzdb, utc, zone, temporal
Last push: 2026-08-07T18:00:58+00:00

## Health v2 (maintenance only)
Score: 59/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 96, release rhythm 8, longevity 66
- inputs: {"age_days": 928, "days_push": 26, "days_rel": 568, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2898, forks 116 (observed 2026-08-28T04:07:28.737913+00:00)

## What it is
Jiff is a high-level datetime library for Rust offering date, time, timestamp, and timezone-aware primitives with DST-safe arithmetic, rounding, and lossless formatting/parsing. It integrates seamlessly with the IANA Time Zone Database, supports RFC 3339/2822 and ISO 8601 formats, and draws heavy inspiration from the TC39 Temporal proposal.

## Use cases
- parse and format RFC 3339 timestamps in Rust
- do timezone-aware date arithmetic that handles DST correctly
- convert datetimes between IANA time zones
- parse dates with strftime/strptime-style formats
- round datetimes to a given unit
- serialize and deserialize zone-aware datetimes with Serde

## When to choose
- you need correct, hard-to-misuse datetime handling in Rust including DST transitions
- you want automatic integration with the system tzdb without manual configuration
- you need lossless round-tripping of zone-aware datetimes
- you want a modern API modeled on the Temporal design instead of chrono or time

## When to avoid
- you need astronomy-oriented or high-precision scientific timekeeping like hifitime provides
- you are locked into an existing codebase built around chrono or time and don't want a migration
- you need calendar systems beyond what Jiff supports, such as non-Gregorian calendars

## Facets
- artifact type: library
- maturity: stable
- function: date-time, parser, serialization
- domain: cross-platform, developer-tools
- platform: rust, cross-platform
- tags: datetime, timezone, calendar, dst, rfc3339, iso8601, tzdb, temporal-inspired, duration-arithmetic, rust-crate, localization

## Member repositories
- BurntSushi/jiff (main) score 59

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:28.737913+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:35:12.139849+00:00, confidence not recorded.
  - readme: https://github.com/BurntSushi/jiff (fetched 2026-08-28T04:07:28.737913+00:00, sha 24858b67c913)
  - registry_crates: https://crates.io/api/v1/crates/jiff (fetched 2026-08-29T09:49:56.180610+00:00, sha 531888f6e5c6)
- Data as of 2026-08-30T08:39:29.467469+00:00.