Free developer tools
Small utilities that run entirely in your browser. Nothing is uploaded, nothing is stored, and none of them ask you to sign up.
Free · no sign-up · runs in your browser
Colour
Tailwind CSS color palette generator
Open →Turn one hex code into a full Tailwind color scale — 11 OKLCH-tuned shades from 50 to 950, with contrast ratios, ready to paste into Tailwind v4's @theme block or a v3 config. Free, no sign-up, runs in your browser.
Colour contrast checker with WCAG suggestions
Open →Check any two colours against WCAG 2 — normal text, large text and UI components — see the ratio and live samples, and get the nearest passing colour when a pair fails, adjusted in OKLCH so the hue stays yours. Free, runs in your browser.
SEO
Meta tag generator with Google SERP preview
Open →Fill in a title, description, canonical and Open Graph image and get the complete <head> snippet — with a live Google result preview that measures your title and description in pixels, not characters, so you can see exactly where they will be cut.
JSON-LD schema generator and validator
Open →Build valid JSON-LD structured data for Article, FAQPage, Product, Organization and BreadcrumbList from a form, or paste existing markup to have it pretty-printed and checked for the mistakes that stop a rich result appearing. Free, runs in your browser.
robots.txt generator with validation
Open →Build a robots.txt from user-agent groups, allow and disallow rules, crawl-delay and sitemap URLs — with presets for allowing everything, blocking AI crawlers, or locking down a staging site, and warnings for the mistakes that quietly block your whole site.
UTM link builder and campaign URL generator
Open →Build correctly encoded UTM tracking links from a URL and your source, medium and campaign — with the existing query string and fragment preserved, values properly percent-encoded, and warnings for the capitalisation and spacing that split one campaign across several rows in an analytics report.
OG image generator — free 1200×630 social cards
Open →Generate an Open Graph image for any page: type a title, pick a theme, download a 1200×630 PNG. Runs entirely in your browser — no account, no upload, no watermark.
Convert
SVG to JSX converter for React components
Open →Paste an SVG and get a React component back — attributes camelCased, class turned into className, style strings converted to objects, xmlns removed, with optional currentColor, a size prop and TypeScript output. Runs entirely in your browser; nothing is uploaded.
Image converter — WebP, AVIF, JPEG and PNG
Open →Convert and resize images to WebP, AVIF, JPEG or PNG at the quality you choose, see exactly how many bytes each one saved, and download them one at a time or as a zip. Everything happens in your browser — no image is uploaded.
JSON to TypeScript — generate interfaces from a payload
Open →Paste a JSON payload and get TypeScript interfaces: merged array shapes, optional properties, and real unions instead of any. Runs in your browser — nothing is uploaded.
Dev
CSS clamp() calculator for fluid typography
Open →Generate a responsive CSS clamp() font size from a minimum and maximum size and the viewport range they should grow across — with the slope and intercept shown, a live preview, and the rendered size at every common screen width. Free, no sign-up.
Favicon generator — .ico, PNG set and manifest
Open →Turn a PNG or SVG, or just a couple of letters, into the full favicon set: 16, 32, 48, 180, 192 and 512 PNGs, a real multi-size favicon.ico, a web app manifest and the <head> tags. Everything runs in your browser — nothing is uploaded.
JSON formatter and validator — free, in your browser
Open →Format, minify and validate JSON in your browser. Broken documents get the exact line and column of the error. Nothing is uploaded, and there is no size limit but your machine.