Crates / castaway
Rust crate · real downloads · data Oct 24, 2026
castaway downloads, and should you depend on it?
Safe, zero-cost downcasting for limited compile-time specialization. crates.io · docs.rs · repository
Owned on crates.io by sagebind · alternatives · is it still maintained?
Feature flags + Cargo.toml picker
Few direct dependents and gaining.
castaway: only 25 crates name it directly; most of its downloads come in through compact_str; 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 +39% 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 paragraphcastaway got 58,337,032 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 626,291 a day, about 4,384,037 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 25 crates name it directly; its downloads arrive through compact_str.
- No release in over a year (last: 0.2.4, Jul 12, 2025). Fine for a finished crate; check open issues and the latest commit before relying on it.
- Still pre-1.0 (0.2.4). Under Cargo's semver rules a 0.x minor bump may break you, so pin the minor version (
castaway = "0.2") and read the changelog on upgrades. - Fit check: license MIT, edition 2018 (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 (626,291 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 castaway
1 of the 1000 crates we track depend on it directly (biggest first).
castaway builds on
Tracked crates its latest version (0.2.4) depends on.
What the chart says
- Weekend quiet days ran at 55% of weekday quiet days (395,490 vs 719,107). A dip that deep is the signature of work-week CI pipelines and developers building on weekdays.
- Biggest day: 1,165,088 on Oct 22, 2026, a quiet day with no release nearby.
Every number
| All-time downloads | 173,364,730 (rank #649 on crates.io by all-time downloads) |
| Downloads in the window | 58,337,032 (Jul 27, 2026 to Oct 23, 2026, 89 days) |
| Within 2 days of a release | 0 (0.0%) |
| Quiet-day median (baseline) | 626,291 a day; weekdays 719,107, weekends 395,490 |
| Release-adjusted downloads | 58,337,032 (release-window days capped at the baseline) |
| Baseline rank | #562 of the 1000 crates we track |
| Quiet-day trend | +57% raw, +13% against the median tracked crate (+39%) |
| Releases in the window | 0 |
| Versions published, ever | 8 |
| Latest version | 0.2.4, published Jul 12, 2025 (license MIT, edition 2018) |
| First published | Jun 21, 2021 |
| Reverse dependencies | 25 |
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 castaway 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.
Badge for your README
Maintainers can show the baseline in a README. It is optional, updates when we refresh the data, and links back here. Preview, then copy:
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Publishing a crate of your own? How to publish a Rust crate to crates.io, step by step.
Categories
Sources
- Daily downloads: crates.io API, /crates/castaway/downloads (last 90 days, all versions), fetched Oct 24, 2026.
- Versions and publish times: crates.io API, /crates/castaway/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.
Up next
Next in rust patterns: Next in Rust patterns by real downloads: 624,830 a day, 1 dependents. Few direct dependents and quiet for years.derive_builder_macroRust crate. Rust macro to automatically implement the builder pattern for arbitrary structs. Real use: 625K downloads a day on quiet days; 1 crates depend on it.Read it next →Also worth your time