Crates / Compare / tokio vs rayon
Rust crates side by side · data Oct 24, 2026
tokio vs rayon
Short answerThey solve different problems and are often used together: tokio for I/O, rayon (via spawn_blocking or a channel) for heavy compute. By steady daily use, tokio is bigger: 3,098,313 real downloads a day against 1,615,491 for rayon (1.9x). 78,796 crates depend on tokio and 11,972 on rayon. tokio last shipped 3 days ago, rayon 6 months ago.
tokio
FoundationalFoundational and steady.
78,796 crates depend on it; downloads jump on release days (1.4x the baseline).
An event-driven, non-blocking I/O platform for writing asynchronous I/O backed applications.
rayon
FoundationalFoundational and steady.
11,972 crates depend on it; no release in the last 90 days, so its count is all steady use.
Simple work-stealing parallelism for Rust
tokiorayon · 100% = that crate's normal quiet day, so a spike to 300% is triple its usual traffic
Every number, side by side
| Same window, same method | tokio | rayon |
|---|---|---|
| Real downloads a day | 3,098,313 | 1,615,491 |
| Crates that depend on it | 78,796 | 11,972 |
| Last release | 1.54.1, 3 days ago | 1.12.0, 6 months ago |
| Trend vs the field | -6% | +3% |
| Release-window share | 11.6% | 0.0% |
| Downloads in the window | 272,815,137 | 149,110,492 |
| All-time downloads | 1,101,468,563 | 618,550,844 |
| Versions published | 201 | 40 |
| License | MIT | MIT OR Apache-2.0 |
| MSRV | 1.85 | 1.80 |
| First published | Jul 1, 2016 | Dec 10, 2015 |
Which to pick
- Pick tokio if the work is waiting on I/O: network calls, sockets, timers, many concurrent connections.
- Pick rayon if the work is CPU-bound: crunching a big collection with
par_iter()across all cores. - Bottom line: They solve different problems and are often used together: tokio for I/O, rayon (via spawn_blocking or a channel) for heavy compute. (checked against each project's docs, Oct 24, 2026)
- 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 (tokio, 78,796 dependents): more eyes, more answered questions, and you may already have it in your tree.
- Check the release dates against your own pace: tokio 3 days ago, rayon 6 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. People search for this pair: Google suggests "tokio vs rayon".