rustls vs openssl

Short answerNew Rust services: rustls. Legacy interop: openssl. By steady daily use, rustls is bigger: 2,763,314 real downloads a day against 945,534 for openssl (2.9x). 5,286 crates depend on rustls and 1,868 on openssl. rustls last shipped 10 days ago, openssl 4 months ago.

rustls

Widely used

Widely used and steady.

5,286 crates depend on it; downloads don't spike on releases.

Rustls is a modern TLS library written in Rust.

openssl

Widely used

Widely used and losing ground.

1,868 crates depend on it; no release in the last 90 days, so its count is all steady use.

OpenSSL bindings

rustlsopenssl · 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	rustls	openssl
Real downloads a day	2,763,314	945,534
Crates that depend on it	5,286	1,868
Last release	0.23.46, 10 days ago	0.10.81, 4 months ago
Trend vs the field	-3%	-12%
Release-window share	10.2%	0.0%
Downloads in the window	248,729,324	79,844,270
All-time downloads	1,037,219,339	434,901,269
Versions published	118	174
License	Apache-2.0 OR ISC OR MIT	Apache-2.0
MSRV	1.71	1.80.0
First published	Aug 27, 2016	Nov 21, 2014

Which to pick

Pick rustls if you want memory-safe TLS with no system libraries to install, TLS 1.2 and 1.3.
Pick openssl if you need legacy protocols or ciphers, FIPS setups tied to OpenSSL, or the system's OpenSSL config.
Bottom line: New Rust services: rustls. Legacy interop: openssl. (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 (rustls, 5,286 dependents): more eyes, more answered questions, and you may already have it in your tree.
Check the release dates against your own pace: rustls 10 days ago, openssl 4 months ago.

Also in this space

socket2Widely usedUtilities for handling networking sockets with a maximal amount of configuration possible intended4,034,112 a day, 1,539 dependents digestWidely usedTraits for cryptographic hash functions and message authentication codes3,862,411 a day, 1,197 dependents block-bufferPulled inBuffer types for block processing of data3,815,018 a day, 23 dependents crypto-commonPulled inCommon traits used by cryptographic algorithms3,766,260 a day, 85 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. People search for this pair: Google suggests "rustls vs openssl".