mini-md5

A minimal MD5 hash function built for the browser. Computes an MD5 hex digest from a UTF-8 string.

Note: This implementation is optimized for size and browser compatibility. It may not be 100% accurate for all edge cases and is not intended for cryptographic or security-sensitive use.

Install

pnpm install mini-md5

Usage

import md5 from 'mini-md5';

md5('hello'); // '5d41402abc4b2a76b9719d911017c592'

Size

~500 bytes (minified + gzipped)

Tests

16 tests — all passing.

| Suite | Tests | |---|---| | RFC 1321 known vectors | 7 | | Unicode edge cases (\0, \uFFFF, emoji, CJK, block boundaries) | 7 | | Random ASCII inputs vs node:crypto | 5 000 000 | | Random Unicode inputs vs node:crypto | 5 000 000 |

Run with:

pnpm test

Benchmarks

Compared against Node's built-in node:crypto MD5 (native C++). mini-md5 is a pure-JS implementation, so it trades some speed for zero dependencies and a tiny bundle footprint.

| Input | mini-md5 | node:crypto | ratio | |---|---|---|---| | Short — 11 bytes | ~1 004 000 ops/s | ~1 062 000 ops/s | on par (1.06×) | | Medium — 56 bytes (two-block boundary) | ~609 000 ops/s | ~967 000 ops/s | 1.59× slower | | Long — 1 000 bytes | ~93 000 ops/s | ~540 000 ops/s | 5.82× slower | | Unicode — mixed multi-byte | ~337 000 ops/s | ~860 000 ops/s | 2.55× slower |

For short strings (the common browser use-case) mini-md5 matches node:crypto throughput. The gap widens for longer inputs because native crypto amortises its fixed overhead more efficiently.

Run with:

pnpm bench