Developer tools

The everyday encoders, formatters and converters, running in your tab so tokens and payloads you paste are never sent to a server.

Free · run in your browser · nothing uploaded

CSS

PX to REM ConverterType a pixel, rem, or em value and the matching unit updates instantly at your chosen base font size.
CSS Clamp CalculatorSet a minimum and maximum font size with the viewport widths where they apply, and get the exact clamp() rule with the math shown step by step.
CSS box shadow generatorAdjust offsets, blur, spread and color, stack multiple shadow layers, and copy the finished CSS.
CSS border radius generatorShape corners with sliders, switch to blob mode for organic shapes, and copy the live border-radius CSS.
CSS Text Shadow GeneratorAdjust offset, blur and color for one or more shadow layers and copy the resulting text-shadow CSS — the preview updates as you drag.
Neumorphism CSS generatorPick a base color, tune the sliders and shape, and copy the generated soft-UI CSS.
CSS grid generatorSet your tracks and gaps, drag across cells to paint named areas, and copy the generated CSS and HTML.
Flexbox playground & generatorExperiment with every flexbox property on live boxes, click an item to fine-tune it, and copy the CSS that reproduces the layout.
SVG Wave GeneratorCreate smooth section-divider waves, preview them live, and export the SVG code or file.
CSS Minifier & BeautifierCompress CSS by removing comments and whitespace, or reformat compact CSS into readable rules — live, entirely on your device.
Color ConverterPick a color or edit any of the fields below — the other formats update as you type.

JSON, YAML, XML and CSV

Encode and decode

Markdown and HTML

Debugging and reference

More developer tools

RGB to CMYK ConverterType a HEX or RGB color to get its CMYK ink percentages, convert a whole list at once, or go back from CMYK to RGB.

About these tools

These are the utilities every developer reaches for and nobody wants to install: encoding and decoding, formatting and validating structured data, converting between formats, generating hashes and identifiers, checking a regular expression against real input.

Running them locally is a practical matter rather than a philosophical one. Pasting a token, a payload or a production configuration into a website that processes it server-side is a genuine disclosure; here the page is static and the work happens in your tab, which you can verify in the network inspector.

Questions people ask

Is it safe to paste a JWT or API response here?

Safer than on a site that processes it server-side: these pages are static files and the decoding runs in your tab, which you can confirm in the network panel of your browser's developer tools. The usual rule still applies — do not paste live production secrets anywhere you do not need to.

What base font size does the px to rem converter assume?

16 px, the default in every major browser, and you can change it. A rem is relative to the root element's font size, so if your stylesheet sets html { font-size: 62.5% }, enter 10 as the base.