Crates / cfg-if
Rust crate · real downloads · data Oct 24, 2026
cfg-if downloads, and should you depend on it?
A macro to ergonomically define an item depending on a large number of #[cfg] parameters. Structured like an if-else chain, the first matching branch is the item that gets emitted. crates.io · docs.rs · repository
Widely used and steady.
cfg-if: 2,759 crates depend on it; downloads don't spike on releases.
How this verdict is decided (4 rules)
- Usage: crates.io reverse dependencies (crates that list it as a dependency): 10,000+ = foundational, 1,000+ = widely used, 100+ = established, under 100 = few direct dependents.
- Direction: the median quiet day in the last 30 days of the window against the first 30, read against the median tracked crate (the whole field moved +36% from late summer to October, so a raw trend says nothing). 10%+ ahead of the field = gaining; 10%+ behind = losing ground; otherwise steady. Steady with no release in 2+ years = quiet for years.
- Release spikes: the median release-window day against the quiet-day baseline: under 1.15x = no spike, 1.15x to 1.3x = small bumps, 1.3x or more = jumps on release days.
- Release recency: days since the newest version that was not yanked, from crates.io publish times.
release window (release day + next day)quiet dayquiet-day median · download the 89 days as CSV
The numbers in one paragraphcfg-if got 390,701,704 crates.io downloads from Jul 27, 2026 to Oct 23, 2026. 2% of them landed within 2 days of one of its 1 release. On the other 87 quiet days it got a median of 4,272,975 a day, about 29,910,825 a week. Capping release days at that baseline leaves 389,572,408 release-adjusted downloads for the window.
What this means if you're choosing a dependency
- Well trodden. 2,759 crates depend on it, so common problems tend to have public answers and breaking changes get noticed fast.
- Actively released. 1.0.5 shipped 38 days ago (Sep 16, 2026).
- Fit check: license MIT OR Apache-2.0, edition 2018, needs Rust 1.32 or newer (from the latest version's manifest).
- Compare it by the baseline, not the raw count. 2% of its 390,701,704 downloads in the window landed within 2 days of a release; the steady number is 4,272,975 a day.
Its place in the dependency graph
Built on cfg-if
14 of the 300 crates we track depend on it directly (biggest first).
What the chart says
- Weekend quiet days ran at 65% of weekday quiet days (2,964,487 vs 4,589,747). A dip that deep is the signature of work-week CI pipelines and developers building on weekdays.
- Biggest day: 6,980,464 on Oct 22, 2026, a quiet day with no release nearby.
Every number
| All-time downloads | 1,628,799,276 (rank #16 on crates.io by all-time downloads) |
| Downloads in the window | 390,701,704 (Jul 27, 2026 to Oct 23, 2026, 89 days) |
| Within 2 days of a release | 9,675,246 (2.5%) |
| Quiet-day median (baseline) | 4,272,975 a day; weekdays 4,589,747, weekends 2,964,487 |
| Release-adjusted downloads | 389,572,408 (release-window days capped at the baseline) |
| Baseline rank | #21 of the 300 crates we track |
| Quiet-day trend | +43% raw, +5% against the median tracked crate (+36%) |
| Releases in the window | 1 |
| Versions published, ever | 17 |
| Latest version | 1.0.5, published Sep 16, 2026 (license MIT OR Apache-2.0, edition 2018, MSRV 1.32) |
| First published | Jul 8, 2015 |
| Reverse dependencies | 2,759 |
Releases in the window
Each one opens a 2-day release window on the chart.
| Version | Published | Downloads that version got (lifetime) |
|---|---|---|
| 1.0.5 | Sep 16, 2026 | 56,832,118 |
How we compute this
crates.io counts every download, including CI runners, mirrors and bots that fetch each new version, so raw counts run high (why, in The Manual). We split the last 89 days into release windows (the day a version of cfg-if was published, plus the next day) and quiet days, and use the median quiet day as the baseline: an upper bound on steady use, never a head count. The method and data come from our study of 90 days of crates.io data from 69 crates, featured in This Week in Rust #674; check any crate live with the real-downloads checker.
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Categories
Sources
- Daily downloads: crates.io API, /crates/cfg-if/downloads (last 90 days, all versions), fetched Oct 24, 2026.
- Versions and publish times: crates.io API, /crates/cfg-if/versions, same fetch.
- Reverse dependencies: crates.io reverse dependencies, same fetch. Dependency edges between tracked crates: each crate's default version, crates.io API.
- Fetched politely (one request every 2 seconds, identified User-Agent) per the crates.io data access policy. Data is crates.io's; the release-window split, baseline and verdict rules are ours, CC BY 4.0.