Crates / Compare / tokio vs smol
Rust crates side by side · data Oct 24, 2026
tokio vs smol
Short answerDefault to tokio; smol is the lean alternative and the one async-std's maintainers now recommend. By steady daily use, tokio is bigger: 3,098,313 real downloads a day against 70,975 for smol (43.7x). 78,796 crates depend on tokio and 766 on smol. tokio last shipped 3 days ago, smol 2.1 years 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.
smol
EstablishedEstablished and gaining.
766 crates depend on it; no release in the last 90 days, so its count is all steady use.
A small and fast async runtime
tokiosmol · 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 | smol |
|---|---|---|
| Real downloads a day | 3,098,313 | 70,975 |
| Crates that depend on it | 78,796 | 766 |
| Last release | 1.54.1, 3 days ago | 2.0.2, 2.1 years ago |
| Trend vs the field | -6% | +37% |
| Release-window share | 11.6% | 0.0% |
| Downloads in the window | 272,815,137 | 7,167,601 |
| All-time downloads | 1,101,468,563 | 26,718,350 |
| Versions published | 201 | 42 |
| License | MIT | Apache-2.0 OR MIT |
| MSRV | 1.85 | 1.63 |
| First published | Jul 1, 2016 | Feb 3, 2020 |
Which to pick
- Pick tokio if you use any tokio-based library (hyper, axum, reqwest, tonic, sqlx) or want the biggest ecosystem and docs.
- Pick smol if you want a small, readable runtime with few dependencies and you control the whole async stack.
- Bottom line: Default to tokio; smol is the lean alternative and the one async-std's maintainers now recommend. (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, smol 2.1 years 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 smol".