once_cell
v1.21.4 StableSingle assignment cells and lazy values.
Quick Verdict
- ✓Actively maintained (updated 15d ago)
- ✓Stable API (1.x for 7+ years)
- ✓Massive adoption (162.5K crates depend on it)
- ✓Permissive license (MIT OR Apache-2.0)
Security
Deep Insights
54.2M downloads in the last 30 days (1.8M/day), up 26% from the previous period.
162.5K crates depend on once_cell — it's part of the Rust ecosystem's core infrastructure. Removing it from your dependency tree would be extremely difficult.
The primary maintainer publishes 78 crates. This suggests deep Rust expertise and long-term commitment to the ecosystem.
The API has been stable (1.x) for over 7 years with 67 releases. This level of maturity means you can depend on it without worrying about breaking changes.
At 34KB, once_cell is lightweight. Small crate size correlates with focused, well-scoped functionality.
12% of releases have been yanked. Check version history before pinning.
Notable dependents include base64, rustix, rustls, tracing-core, ahash. When high-quality crates choose once_cell, it's a strong quality signal.
Health Breakdown
Recency, release consistency, active ratio
Yanked ratio, deps, size, maturity, features
Reverse deps, ownership, ecosystem
Downloads, momentum, growth trend
Docs, repo, license, metadata
Download Trend
Top Dependents
Most downloaded crates that depend on once_cell
Version Adoption
Release Timeline
Feature Flags
default =["std"]
