Developer tools that run in your browser
ProperScript is a collection of 101 small, single-purpose utilities for
the jobs that come up constantly in development work: formatting a JSON payload,
decoding a token, converting a CSV export, generating a .gitignore,
checking what a cron expression actually does. Each one does a single thing, on
one page, with no setup.
Everything runs locally
Every tool here executes entirely in your browser using JavaScript. Nothing you paste is uploaded to a server, stored, or logged — the data never leaves your machine.
This isn't a privacy slogan; it's the reason these tools are usable at work. A great many online utilities process your input server-side, which makes them genuinely unsafe for production payloads, access tokens, customer exports, or anything under an NDA. Running locally removes that question entirely. It also means the tools keep working with no network connection once a page has loaded, and there's no upload wait on large files.
How the tools are organized
- Code & developer tools — format, validate, diff, and inspect JSON, CSS, HTML, SQL, regex, cron, and JWT.
- Data format conversions — move between CSV, TSV, JSON, XML, and YAML in any direction.
- Text tools — count, transform, sort, deduplicate, compare, and clean text.
- Encode & decode — Base64, URL encoding, HTML entities, hex, binary, and JWT.
- Generators — passwords, API keys, UUIDs, QR codes, and project boilerplate.
- Reference — cheat sheets for HTTP status codes, regex, vim, git, Markdown, and ASCII.
- Image utilities — favicon sets and Base64 image encoding.
No account, no quotas
There's no sign-up, no usage limit, and no paid tier holding back the useful features. Open a tool, use it, close the tab. Each page also carries a short explainer covering what the tool does, the common mistakes, and when you'd want something else instead.