Crates / autocfg
Rust crate · real downloads · data Oct 24, 2026
autocfg downloads, and should you depend on it?
Automatic cfg for Rust compiler features crates.io · docs · repository
Few direct dependents and steady.
autocfg: only 82 crates name it directly; most of its downloads come in through num-traits and memoffset; no release in the last 90 days, so its count is all steady use.
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 paragraphautocfg got 335,173,321 crates.io downloads from Jul 27, 2026 to Oct 23, 2026 with no new version in that window, so every day is a quiet day: a median of 3,840,273 a day, about 26,881,911 a week. With no release spikes to remove, its whole count is the steady baseline.
What this means if you're choosing a dependency
- You rarely add this one yourself. Only 82 crates name it directly; its downloads arrive through num-traits, memoffset.
- Released this year. The latest version, 1.5.1, is from May 22, 2026 (5 months ago).
- Fit check: license Apache-2.0 OR MIT, needs Rust 1.0 or newer (from the latest version's manifest).
- Its raw count is a fair read. Under 1% of its downloads in the window came from release windows, so the raw number and the baseline (3,840,273 a day) tell the same story.
Alternatives that do a similar job
Crates that share its crates.io category or keywords, most similar first. Each line is the crate's own description, then how it compares on the same data.
Its place in the dependency graph
Built on autocfg
2 of the 300 crates we track depend on it directly (biggest first).
What the chart says
- Weekend quiet days ran at 60% of weekday quiet days (2,477,274 vs 4,109,855). A dip that deep is the signature of work-week CI pipelines and developers building on weekdays.
- Biggest day: 5,754,767 on Oct 22, 2026, a quiet day with no release nearby.
Every number
| All-time downloads | 1,450,861,395 (rank #26 on crates.io by all-time downloads) |
| Downloads in the window | 335,173,321 (Jul 27, 2026 to Oct 23, 2026, 89 days) |
| Within 2 days of a release | 0 (0.0%) |
| Quiet-day median (baseline) | 3,840,273 a day; weekdays 4,109,855, weekends 2,477,274 |
| Release-adjusted downloads | 335,173,321 (release-window days capped at the baseline) |
| Baseline rank | #31 of the 300 crates we track |
| Quiet-day trend | +29% raw, -5% against the median tracked crate (+36%) |
| Releases in the window | 0 |
| Versions published, ever | 18 |
| Latest version | 1.5.1, published May 22, 2026 (license Apache-2.0 OR MIT, MSRV 1.0) |
| First published | May 30, 2018 |
| Reverse dependencies | 82 |
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 autocfg 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/autocfg/downloads (last 90 days, all versions), fetched Oct 24, 2026.
- Versions and publish times: crates.io API, /crates/autocfg/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.