Developer Tools

The formatters are one engine with different front doors

HTML Formatter, CSS Formatter, JS Formatter, JSON Formatter, XML Formatter and SQL Formatter are single-language pages over the same machinery that Code Formatter exposes for nineteen languages at once — HTML, CSS and JavaScript through to Java, Kotlin, Rust, PHP, Python, SQL and Protobuf. Prettier does the printing, with Ruff for Python, and both are compiled to run in the browser rather than called on a server.

Use a single-language page when you already know what you have and want it opened, indented and gone; use Code Formatter when you are pasting from a log or a ticket and want to pick the language yourself. The defaults are the ones most projects settle on anyway: two-space indentation and an 80-column print width.

Understand what a formatter is not. These tools re-print your code from a parse tree; they do not lint it, rename anything, remove dead code or change behaviour. A minified stylesheet comes back readable with its declaration order and comments intact, and a single-line HTML document comes back as a structured tree, but nothing about the logic has been touched.

Formatting as a validity check

Because the printers rebuild a document from a parse tree, they cannot print what they cannot parse. XML Formatter refuses malformed XML outright while preserving CDATA sections, comments, the DOCTYPE and xml:space when the input is sound, so a successful format doubles as proof the document is well formed. The same reasoning applies to JSON Formatter, which validates before it pretty prints and points at the position it choked on.

JSON Formatter is the one to reach for on an unfamiliar payload rather than a merely ugly one: as well as pretty printing and minifying, it gives you a collapsible tree to explore and a way to find the path to a value, which beats scrolling through four thousand lines looking for the field you were promised.

SQL Formatter uppercases keywords and puts one clause per line, and it copes with the constructs that defeat naive formatters — common table expressions, window functions and MySQL backtick quoting. It formats standard SQL; a heavily dialect-specific script may come back reformatted in a way your database still accepts but your linter argues with.

Checking a thing before it runs

Regex Tester runs your pattern against your own sample text and highlights every match in place. It uses your browser's own regular expression engine, which cuts both ways and is worth being explicit about: error messages read exactly as they will in your JavaScript, and lookbehind or Unicode property escapes behave exactly as they will in that runtime — but a pattern destined for PCRE, Python or Go is being checked against the wrong dialect, and the differences bite around named groups, escapes and lazy quantifiers.

Cron Parser turns a crontab expression into a plain-English schedule as you type. The value is in reading it before it goes live: "at 00:00 on day-of-month 1 in January" is instantly recognisable as the yearly job you did not mean to write, in a way that 0 0 1 1 * never is.

Colours and data shapes

Color Picker pairs your system colour picker with one editable hex field and re-derives HEX, RGB and HSL from it, so you can copy whichever notation the file you are editing wants. It is sRGB only — no CMYK, no alpha channel and no palette management.

JSON to CSV flattens JSON into a spreadsheet, turning nested objects into dotted column names such as address.city, and writes the file with a UTF-8 marker so Excel opens accented characters correctly instead of turning them into mojibake. Its mirror image, CSV to JSON, lives with the file converters, along with the Excel and CSV workbook tools.

Why running locally matters here specifically

The paste that goes into a formatter is very often the one you should be most careful with: an API response with a customer record in it, a config file with a hostname, a query that names your schema. Hosted formatters receive all of that. These pages load their engine once and then work entirely on your machine, so the text you paste is never sent anywhere and there is no service to trust with it afterwards.

The trade-off is honest: the first visit downloads a formatting engine, so a page takes a moment to become useful on a cold cache, and very large inputs are limited by your own memory rather than by a server's. For tokens, hashes and encodings there is a matching set under security tools, which follows the same rule.