Crates / Compare / either vs arrayvec
Rust crates side by side · data Oct 24, 2026
either vs arrayvec
Short answerBy steady daily use, either is bigger: 3,049,603 real downloads a day against 1,733,744 for arrayvec (1.8x). 1,488 crates depend on either and 1,215 on arrayvec. either last shipped 18 days ago, arrayvec 4 months ago.
either
Widely usedWidely used and steady.
1,488 crates depend on it; small bumps on release days (1.17x the baseline).
The enum `Either` with variants `Left` and `Right` is a general purpose sum type with two cases.
arrayvec
Widely usedWidely used and steady.
1,215 crates depend on it; no release in the last 90 days, so its count is all steady use.
A vector with fixed capacity, backed by an array (it can be stored on the stack too). Implements fixed capacity ArrayVec and ArrayString.
eitherarrayvec · 100% = that crate's normal quiet day, so a spike to 300% is triple its usual traffic
How they relate
- Often used together: 1 tracked crate depend on both (schemars). They are not always either/or.
Every number, side by side
| Same window, same method | either | arrayvec |
|---|---|---|
| Real downloads a day | 3,049,603 | 1,733,744 |
| Crates that depend on it | 1,488 | 1,215 |
| Last release | 1.19.0, 18 days ago | 0.7.8, 4 months ago |
| Trend vs the field | -3% | +2% |
| Release-window share | 5.3% | 0.0% |
| Downloads in the window | 272,811,687 | 157,353,540 |
| All-time downloads | 1,137,983,028 | 640,435,610 |
| Versions published | 36 | 57 |
| License | MIT OR Apache-2.0 | MIT OR Apache-2.0 |
| MSRV | 1.63.0 | 1.51 |
| First published | Sep 14, 2015 | May 19, 2015 |
Which to pick
- Downloads tell you what is common, not what fits. Each crate's own description above says what it is for; when the jobs differ, pick by the job.
- When both fit, prefer the one more crates depend on (either, 1,488 dependents): more eyes, more answered questions, and you may already have it in your tree.
- Check the release dates against your own pace: either 18 days ago, arrayvec 4 months ago.
Also in this space
Method
Real downloads = the median day with no release that day or the day before, from the crates.io API (Jul 27, 2026 to Oct 23, 2026). Raw crates.io counts include CI and bots and run high (why); the method is from our 90-day study.
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