Rust crate alternatives · data Oct 24, 2026
Alternatives to pem
Short answerThe closest alternatives to pem on crates.io data are tinyvec (2.3M real downloads a day), siphasher (2M real downloads a day), base64ct (1.3M real downloads a day). Of the 8 we list, the most used is hashbrown, and 8 shipped a release in the last year. pem itself gets 1,031,308 a day with 419 dependents.
Every alternative we found
| Alternative | Real downloads a day | vs pem | Dependents | Last release | Why it is listed | |
|---|---|---|---|---|---|---|
| tinyvec Established | 2,308,962 | 2.24x | 270 | 41d | keyword "no-std", keyword "no_std" | compare |
| siphasher Established | 1,957,258 | 1.90x | 274 | 29d | category Cryptography, keyword "no-std" | compare |
| base64ct Established | 1,305,115 | 1.27x | 439 | 9mo | category Cryptography, keyword "pem" | compare |
| pkcs1 Pulled in | 704,103 | 0.68x | 65 | 19d | category Cryptography, keyword "pem" | compare |
| ark-std Established | 346,455 | 0.34x | 361 | 6mo | category Cryptography, keyword "no_std" | side by side |
| hashbrown Widely used | 8,927,960 | 8.66x | 2,468 | 6mo | keyword "no_std" | compare |
| indexmap Widely used | 4,883,122 | 4.73x | 6,422 | 49d | keyword "no_std" | compare |
| serde Foundational | 4,327,945 | 4.20x | 133,588 | 3mo | keyword "no_std" | compare |
How to choose
- Same job, not the same API. Each line is listed because it shares a crates.io category or keyword with pem; read its description before you swap.
- More dependents means more answered questions and a smaller chance it disappears.
- Check the last release against how fast you need fixes. For pem: is it still maintained?
Rules
Alternatives = tracked crates (top 1000 by downloads) that share a specific crates.io category (2 points each) or keyword (3 points each) with pem, most similar first; its own parts (same name prefix) and crates it depends on or that depend on it are left out, because those are companions, not substitutes. Real downloads = quiet-day median, crates.io data Oct 24, 2026. Built when we find 3 or more.
Up next
The closest alternative: Established and steady. 2,308,962 real downloads a day.tinyvecRust crate. `tinyvec` provides 100% safe vec-like data structures. Real use: 2.3M downloads a day on quiet days; 270 crates depend on it.Read it next →Also worth your time