Guide

The Developer's Guide to Free Browser Tools

Most developer utilities exist to remove a small, repeated friction: reading a query that arrived on one line, working out what a cron expression does, writing an interface for a response you already have in front of you. None of them justify installing anything, and none of them should require sending your code to a server. These run in the browser and cover the jobs that come up mid-task.

Free foreverNo sign-upRuns in your browser
01

Make unreadable code readable again

The SQL Formatter handles nineteen dialects, which matters because vendor syntax is the usual failure point — T-SQL's bracketed identifiers, PostgreSQL's double-colon casts and BigQuery's backticked tables are all valid SQL and all rejected by the wrong parser. The Code Beautifier does the same for minified HTML, CSS and JavaScript, with one honest caveat: it restores formatting, not names. A minifier renames variables to single letters and that information is gone from the file, so you get readable working code rather than the original source.

02

Stop hand-writing types and diffing JSON by eye

JSON to TypeScript infers interfaces, Go structs or Python dataclasses from a sample, and compares every object of a shape to decide which fields are genuinely optional — which is why pasting several representative records produces much better types than one. JSON Diff compares parsed structure rather than lines, so key order and indentation are ignored entirely and only real changes appear, each with the path where it lives. Two files differing only in formatting come back identical, which a text diff would never tell you.

03

Schedules, markup and repository housekeeping

Nobody remembers cron syntax, and a description alone can still be misread — so the Cron Generator shows the next five run times, which catches a supposedly weekly job firing daily in seconds. Times display in your browser's zone while your server almost certainly runs in UTC, and that mismatch is the most common cause of a job firing at an unexpected hour. The Markdown Editor gives a live sanitised preview, the Markdown and HTML converter goes both ways, and the gitignore Generator assembles a deduplicated file from twenty templates.

04

The small stuff that interrupts you

Colour conversion between HEX, RGB, HSL, HSV and CMYK with a built-in WCAG contrast check, so you can tell immediately whether white or black text will be legible. Diff checking for arbitrary text, Unix timestamp conversion across nineteen time zones, number base conversion including two's complement, and HTML entity encoding. Individually trivial, collectively the reason people keep a tools tab open.

From reading to doing

Put it into practice.

Every tool in this guide is free, private, and runs entirely in your browser.

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