Building a Hash Generator with Web Crypto API and a Pure-JS MD5 Fallback

Every developer runs into hashing at some point. Checking file integrity, storing password fingerprints, verifying API payloads, generating cache keys. Most reach for a CLI tool ( shasum , md5sum ) or an npm package. But what if you could hash text and files directly in the browser — no installs, no dependencies, no server? I built a Hash Generator that supports MD5, SHA-1, SHA-256, SHA-384, and SHA-512. All client-side. Here's how it works under the hood. The Web Crypto API Does Most of the Work Modern browsers ship with crypto.subtle — a native cryptographic API that handles SHA algorithms with hardware-accelerated performance. async function computeHash ( data : Uint8Array , algorithm : Algorithm ): Promise < string > { if ( algorithm === " MD5 " ) return md5 ( data ); const hashBuffer = await crypto . subtle . digest ( algorithm , data ); return Array . from ( new Uint8Array ( hashBuffer )) . map ( b => b . toString ( 16 ). padStart ( 2 , " 0 " )) . join ( "" ); } That's it for SHA