Stackblip, explained.

The short version

Stackblip is a free, browser-only toolbox for people who write software. Five tools — a JWT decoder, a cron expression builder, a multi-hash generator, an HTTP status code reference, and a conventional commit composer — each one doing a single job properly, each one running entirely on your machine.

There's nothing to install, nothing to sign up for, and nothing to trust on faith. Open your browser's Network tab while using any tool here and you'll see it make exactly zero requests. That's the whole site in one sentence.

Why this exists

Stackblip started as a personal gripe. Every week I'd paste tokens, checksums and schedules into "free" tool sites that treated my input as the product — analytics on every keystroke, three ad networks fighting over the layout, a cookie banner longer than the tool itself. The tools worked, technically. They just made me the merchandise.

So I built the versions I actually wanted: pages that compute your input locally and forget it the moment you close the tab. No accounts, because there's nothing to store. No analytics, because your debugging session at 2am is nobody's business. No framework, because a JWT decoder doesn't need a two-megabyte JavaScript bundle to decode some base64.

And then I kept going — because writing these tools properly turned out to be genuinely fun, and because a small, sharp, honest toolbox is the kind of thing the web used to be good at. Stackblip is my attempt to bring a little of that back.

Is there a business model? Barely, and that's the point. The site may show a few unobtrusive ads someday — enough to cover hosting, nothing more. No premium tier, no features locked behind a paywall, nothing sold to anyone. The tools are free the way a public park is free.

What's inside

Five tools, one philosophy — input goes in, answer comes out, nothing is kept:

What the site commits to

1. 01

   Your input never leaves the tab

   Every tool runs in your browser. Open the Network tab, count the requests: zero. If that ever changes, this page changes first.

2. 02

   Nothing is hidden from you

   The entire site is hand-written HTML, CSS and JavaScript. View Source shows you everything, because there's nothing to minify into obscurity.

3. 03

   Correctness over cleverness

   The hash engines are checked against published test vectors, the cron engine handles the infamous day-of-month / day-of-week OR rule, and the JWT decoder reads UTF-8 properly. Boring, verified correctness beats flashy approximation.

4. 04

   Honest labels

   MD5 is marked "broken" and SHA-1 "weak" right in the interface, even though they're convenient to use. A tool should tell you the truth even when it's inconvenient.

5. 05

   Fast by construction

   No framework, no build pipeline, no bundle. The pages load on hotel Wi-Fi like it's 2015 — in a good way.

What this is not

Stackblip is a working developer's pocket knife, not a security audit. A few honest boundaries, because you deserve them:

• Decoding is not verifying. The JWT tool reads tokens; only a server holding the right key can trust them. Never make authorization decisions from a decoded payload.
• Not for passwords. The hashes here are for checksums, dedup and learning. Storing passwords needs slow, salted functions like bcrypt or Argon2 — a different tool for a different job.
• As-is, like everything on the web. For anything career-critical — a release checksum, a production token — verify with a second source. The disclaimer page says this in the formal voice.
• One developer, not a company. Updates ship when they're right, not on a sprint schedule. That's the trade-off for a site with no investors to please.

Who's behind it

Stackblip is built and maintained by a working developer — one person, one text editor, no team, no office, no funding. Everything here was written by hand, tested against real-world inputs, and published for the simple reason that it's useful.

If one of these tools ever saves you an hour, that's the whole point. If you find a bug, I'd genuinely like to know about it — that's how small sites like this stay sharp. Tool suggestions are welcome too: if it's useful, runs client-side, and doesn't need your data, it's a candidate.