10 New Developer-Tool Snippets: JWTs, Regex, Subnets, and Data Viz Built From Real Math
10 free dev-tool snippets — JWT decoder, regex tester, CIDR calculator, violin plots & more — real algorithms, not mockups. Copy-paste HTML/CSS/JS.
10 New Developer-Tool Snippets: JWTs, Regex, Subnets, and Data Viz Built From Real Math
Most "developer tool" pages on the web are wrappers around a paste box that quietly ships your input to a server. A JWT decoder that emails you your own token, a regex tester that runs on someone else's backend, a base64 decoder you have to trust not to log what you typed — none of that should be necessary for problems this small. Every snippet below runs entirely in the browser: real base64url decoding, a real RegExp engine, real 32-bit bitwise subnet math, a real Gaussian kernel density estimate for the violin chart — nothing faked, nothing transmitted anywhere. These ten are the newest addition to the library, and they lean deliberately into two categories that hadn't gotten much attention yet: small developer utilities you'd normally open a random website for, and statistical/relational charts built by hand with SVG instead of a charting library. Every one is a live, interactive preview you can try right here in the article, and each exports to React, Vue, Ang…
