zerocopy vs embedded-io

Short answerBy steady daily use, zerocopy is bigger: 3,245,504 real downloads a day against 733,222 for embedded-io (4.4x). 878 crates depend on zerocopy and 337 on embedded-io. zerocopy last shipped 11 days ago, embedded-io 13 months ago.

zerocopy

Established

Established and steady.

878 crates depend on it; small bumps on release days (1.19x the baseline).

Zerocopy makes zero-cost memory manipulation effortless. We write "unsafe" so you don't have to.

embedded-io

Established

Established and steady.

337 crates depend on it; no release in the last 90 days, so its count is all steady use.

Embedded IO traits

zerocopyembedded-io · 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	zerocopy	embedded-io
Real downloads a day	3,245,504	733,222
Crates that depend on it	878	337
Last release	0.8.63, 11 days ago	0.7.1, 13 months ago
Trend vs the field	-6%	+7%
Release-window share	18.2%	0.0%
Downloads in the window	295,559,617	67,775,070
All-time downloads	1,048,972,923	157,899,562
Versions published	174	10
License	BSD-2-Clause OR Apache-2.0 OR MIT	MIT OR Apache-2.0
MSRV	1.56.0	1.81
First published	Aug 15, 2018	May 6, 2022

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 (zerocopy, 878 dependents): more eyes, more answered questions, and you may already have it in your tree.
Check the release dates against your own pace: zerocopy 11 days ago, embedded-io 13 months ago.

Also in this space

num-convPulled in`num_conv` is a crate to convert between integer types without using `as` casts. This provides better...2,114,479 a day, 4 dependents ciboriumEstablishedserde implementation of CBOR using ciborium-basic775,492 a day, 902 dependents ciborium-llPulled inLow-level CBOR codec primitives775,035 a day, 10 dependents bytemuckWidely usedA crate for mucking around with piles of bytes1,311,229 a day, 4,338 dependents

Compare 4 of them side by side →

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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