Developer Tools
Browse 20 free browser tools for developer tasks, available directly in your browser.
20 tools
About these tools
These are the small utilities that interrupt real work: a query that arrived as one unreadable line, a config file that will not parse, a token whose expiry you need to read, a shadow that needs four numbers adjusted together. Each one does a single job and hands you something you can paste.
The formatters and validators are parser-based rather than regular expressions, which matters for the cases that actually bite — a keyword inside a string literal is text, not a keyword, and a tool that does not know the difference will corrupt your data while appearing to work.
Nothing you paste is transmitted. That is worth knowing for the JWT inspector in particular: tokens routinely contain user identifiers and claims, and pasting a production token into a remote service is a habit worth not having. Even so, prefer a test token — the safest secret is one that was never in a browser at all.
Format and validate
Make a file readable, or find out why it will not parse.
- SQL FormatterFormat SQL online for free with full control: pick from 19 dialects including MySQL…Developer Tools
- SQL BeautifierMake a query readable in one click by choosing a style preset rather than configuring anything.Developer Tools
- SQL MinifierStrip comments and newlines to put a query on a single line, for a config value…Developer Tools
- YAML ValidatorCheck YAML for syntax errors and get the line and column where parsing failed…Developer Tools
- TOML ValidatorValidate a TOML configuration file and see exactly where it stops parsing…Developer Tools
- XML BeautifierTurn a single-line XML payload into an indented document you can read…Developer Tools
CSS generators
Build a value visually and copy the rule.
- CSS Box Shadow GeneratorBuild a box-shadow by dragging offset, blur, spread and colour, stack multiple layers…Developer Tools
- CSS Border GeneratorSet border width, style, colour and per-corner radius visually, then copy the CSS.Developer Tools
- CSS Grid GeneratorLay out a CSS grid by choosing rows, columns and gaps, place items on it…Developer Tools
- Flexbox GeneratorSee what justify-content, align-items, wrap and direction actually do to a row of boxes…Developer Tools
- CSS Animation GeneratorCompose a keyframe animation with timing, easing and delay, watch it run…Developer Tools
- SVG Path GeneratorBuild an SVG path by placing points and curves, and read the d attribute it produces…Developer Tools
Identifiers, text and encoding
Inspect a token, check a UUID, convert between markup formats.
- JWT InspectorDecode a JSON Web Token to read its header, claims and expiry…Developer Tools
- UUID ValidatorConfirm a UUID is well formed and find out which version it is, so you know whether it is random…Developer Tools
- UUID ConverterConvert a UUID between hyphenated, plain, URN and Base64 forms, and back again…Developer Tools
- Markdown EditorWrite Markdown beside a rendered preview, with the formatting applied as you type.Developer Tools
- Markdown to HTMLTurn Markdown into clean HTML for a CMS or a template, with tables…Developer Tools
- HTML to MarkdownConvert HTML into Markdown, keeping headings, lists, links and code while dropping the wrapper…Developer Tools
- QR Code GeneratorMake a free QR code for a link, text, Wi-Fi network or contact card and download it as PNG or SVG.Developer Tools
- Regex Cheat SheetA reference for regular-expression syntax — anchors, classes, quantifiers, groups and lookaround…Developer Tools
Related categories
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