Developer Tools — JSON, YAML, JWT, Hash, CIDR, Cron, chmod

Format and convert

Data in, the same data out in a shape you can read or send.

JSON formatter and validatorPretty-print, minify, sort keys, exact error line.YAML ↔ JSONAnchors, merge keys and multi-document files.JSON ↔ CSVRFC 4180 quoting, delimiters, row validation.Base64 encoder and decoderText or file, URL-safe alphabet, honest hex view.URL encoder and decoderComponent or whole URL, plus a query breakdown.Number base converterBinary, octal, decimal, hex and base36 with BigInt.JWT decoderHeader, payload and claim times — no false "valid".HTML entity encoder and decoderNamed or numeric entities, with an honest decoder..env to JSONQuotes, escapes and duplicate keys the way dotenv reads them.Markdown table generatorCSV or JSON into an aligned GFM table, and back.Data URI converterA file to a data URI, or a data URI back to a file.TOML ⇄ JSONTOML 1.0 with line numbers, nulls refused.SQL formatterDialect-aware formatting; no execution, no false validation.XML formatterIndents without losing comments or CDATA; well-formedness only.DOCX to MarkdownWord structure to Markdown, HTML or text; images are counted.

Generate and protect

Values produced by the browser CSPRNG, never by Math.random.

Inspect and compare

Find what changed, when it happened, and what a pattern matches.

Why these belong in a browser

Developer tools are where credentials leak. A JWT pasted into a decoder, a .envformatted by a formatter, a production JSON response dropped into a beautifier — each one hands a third party a live secret and hopes the logs are not kept. Every tool here reads its input in the tab and writes its output in the tab. The only network requests a tool page makes are for its own static assets.

That constraint is also why some features are missing. There is no signature verification in the JWT decoder, because verification needs a key and a key cannot be kept in a page. There is no password-strength guarantee in the random generator, because entropy describes the draw, not how you use the value. Where a tool cannot be honest, it says so instead of showing a green tick.

What each tool will not do

The JSON formatter refuses JSON5, comments and trailing commas rather than repairing them.
The Base64 decoder shows binary payloads as hex instead of lossy text.
The hash generator marks MD5 and SHA-1 as weak, even while computing them.
The regex tester caps its input because a backtracking pattern cannot be interrupted.
The text diff counts whitespace, so two files that look the same but differ are reported as different.

The document converters are on the student and utility tools page, and the image and PDF tools each have their own hub: images andPDFs.

Developer tools questions

Are all of these tools free and account-free?

Yes. There is no sign-up, no paywall, no watermark and no daily limit. Each tool page states its own limits — characters per run, file size, batch size — and enforces them.

Is my data uploaded anywhere?

No. Every tool in this group runs on JavaScript in your tab: parsing, encoding, hashing and comparison all use browser APIs and bundled libraries. There is no upload endpoint, and you can confirm it in the network panel while using a tool.

Do these replace command-line tools?

They replace the one-off checks: formatting a payload someone pasted into chat, reading a token, verifying a checksum, comparing two config files. For scripted work, use jq, openssl, sha256sum and git diff — this site does not pretend a page is a build system.

Which tools run automatically and which need a button?

The text conversions update as you type. UUID, random string and regex testing run on a button press, on purpose: generating values on every keystroke and running a pattern that may backtrack are both actions worth asking for.

Why is there no code beautifier for CSS, HTML or JavaScript?

Because those tools are usually judged by output that only a language parser can guarantee, and shipping a half-correct formatter would violate this project's rule against fake functionality. The Markdown and HTML converters that do exist are backed by real parsers and tested end to end.