Crates / once_cell / Maintained?
Rust crate maintenance · data Oct 24, 2026
Is once_cell still maintained?
Short answerYes, on a slow release cadence. once_cell's newest version, 1.21.4, shipped on Mar 12, 2026 (7 months ago). It has had 1 release in the last 12 months and 6 in 24, and 59 non-yanked versions since 2018. 8,656 crates depend on it and it gets 3,785,180 real downloads a day.
The signals
- Last release: 7 months ago (1.21.4, Mar 12, 2026).
- Release rhythm: 1 in the last year, 6 in two.
- Still used: 3,785,180 real downloads a day, quiet-day trend -3% against the field.
- Yanked versions: 8 (a normal sign of a maintainer fixing a bad release).
Releases per quarter, last 2 years
| Quarter | Releases | |
|---|---|---|
| Oct 27 to Jan 25, 2025 | 0 | |
| Jan 26 to Apr 26, 2025 | 5 | |
| Apr 27 to Jul 26, 2025 | 0 | |
| Jul 27 to Oct 25, 2025 | 0 | |
| Oct 26 to Jan 24, 2026 | 0 | |
| Jan 25 to Apr 25, 2026 | 1 | |
| Apr 26 to Jul 25, 2026 | 0 | |
| Jul 26 to Oct 24, 2026 | 0 |
If you need something more active
Rules
From crates.io release history (non-yanked versions), fetched Oct 24, 2026: last release within 6 months = actively maintained; within 18 months = slow cadence; older with 1,000+ dependents = quiet and widely relied on; otherwise quiet. We do not read commits or issues: a crate can be finished and safe without new releases, and active on GitHub without publishing. Before you rely on it, look at the repository for recent commits and open issues. Run cargo audit for security advisories.
Up next
The full numbers: Widely used and steady. Chart, alternatives and badge.once_cellRust crate. Single assignment cells and lazy values. Real use: 3.8M downloads a day on quiet days; 8,656 crates depend on it.Read it next →Also worth your time