Free Dev & Web

A toolbox for building the web: SQL formatter, WCAG color contrast checker, CSS gradient and box-shadow generators, flexbox/grid playground, favicon and social-image generators, sitemap and robots.txt builders, SVG compressor, image format converter, and viewport info. Everything runs client-side — paste, generate, copy.

Live

SQL Formatter

Clean up messy SQL — uppercase keywords, indent clauses.

Open tool → Live

Color Contrast Checker

Real WCAG contrast ratios — AA/AAA pass or fail.

Open tool → Live

CSS Gradient Generator

Build linear and radial gradients with live preview.

Open tool → Live

Box Shadow Generator

Design box shadows visually, copy the CSS.

Open tool → Live

Favicon Generator

Make a favicon from a letter or emoji — download PNG.

Open tool → Live

OG Image Generator

Design 1200×630 social preview images, download PNG.

Open tool → Live

Sitemap Generator

Turn a URL list into a valid sitemap.xml.

Open tool → Live

robots.txt Generator

Build robots.txt rules with a visual rule builder.

Open tool → Live

SVG Compressor

Shrink SVG files — see bytes saved instantly.

Open tool → Live

Flexbox / Grid Playground

Learn flexbox and grid with live examples.

Open tool → Live

Image Format Converter

Convert images between JPG, PNG, and WebP.

Open tool → Live

Viewport Info

Your screen, viewport, and device specs at a glance.

Open tool →

Related categories

Text & Files Utilities Ciphers & Codes

More from the codex

Live

Browse all categories

Every category on the codex, from study tools to ciphers — pick your starting point.

Browse → Live

Prompt Simulator

Practice prompt engineering: write prompts, get scored 0–10.

Open tool → Live

GPA Calculator

Semester and cumulative GPA with weighted scales and a target planner.

Open tool →

About these dev & web

Every tool below is free, works in your browser, and needs no account.

Do these tools upload my code?
No. All processing happens in your browser — your SQL, SVGs, and images never touch a server.
What does the contrast checker test?
It computes the real WCAG contrast ratio between two colors and tells you whether the pair passes AA or AAA for normal and large text.
Can I download the generated files?
Yes — favicons, OG images, converted images, sitemaps, and robots.txt all download directly from the tool.