Free online tools for web developers
109 fast, private tools for everyday dev work — formatters, converters, generators and SEO checkers. No signup, free to use.
Checks ~70 SEO, speed, schema, social & security issues · press Ctrl K to search all 109 tools · runs in your browser where possible
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Ranked by what people use mostRegex TesterType a pattern and watch matches highlight live in your test text. Inspect every capture group, try…Diff CheckerPaste an original and a changed version to see added, removed and modified lines side by side — with the…Tailwind Color GeneratorPaste one brand colour and get a balanced 11-step shade scale (50 to 950) built in OKLCH — with contrast…Clamp CalculatorEnter a minimum and maximum size and the viewport range — get a zoom-friendly clamp() value with the maths…JSON FormatterPaste JSON to pretty-print, minify or validate it. Errors are pinpointed to the exact line and column with…Base64 Encode / DecodeConvert text to Base64 and back with full UTF-8 support (accents, emoji), switch to URL-safe Base64, or…JWT DecoderPaste a JSON Web Token to inspect its header and payload, check when it expires and verify its signature.…Image CompressorShrink photos and graphics by 50–90% without visible quality loss. Batch-compress, convert to WebP or…QR Code GeneratorGenerate a QR code for a link, Wi-Fi login, contact card, email, phone number or SMS. Customise colours,…README GeneratorFill in a few fields and get a clean, GitHub-ready README.md — badges, installation, usage example,…SEO Checker & Site AuditPaste a URL to run up to 70 on-page SEO checks in seconds. You get a score, a prioritised list of issues…Broken Link CheckerEnter a page URL and every link on it — plus images, scripts and stylesheets if you like — is tested live,…
Webflow & Figma Tools
All 8 webflow toolsHTML & CSS to WebflowPaste HTML and its CSS, click Copy to Webflow and paste into the Designer — you get real Div Blocks,…Class Name GeneratorDescribe a section in plain words — “hero with tagline, heading, two buttons and an image on the right” —…Class Name Typo CheckerPaste HTML or enter a URL to audit every class name: catch typos like hero_heding, duplicates spelled…SVG to WebflowPaste an SVG from Figma and copy it to Webflow as real Custom Elements — every <svg>, <path> and <g>…Figma CSS to WebflowTurn Figma’s “Copy as CSS” output into tidy values you can type straight into Webflow’s Style panel —…Markdown to Webflow Rich TextPaste Markdown, check the preview and copy it as formatted rich text — headings, lists, links and bold…HTML to Webflow Rich TextPaste messy HTML — from an old site, WordPress export, Google Docs or Word — and get clean semantic markup…Lottie JSON OptimizerMake Lottie animations load faster in Webflow and on any site by stripping data the player doesn’t need —…
SEO Tools
All 28 seo toolsSEO Checker & Site AuditPaste a URL to run up to 70 on-page SEO checks in seconds. You get a score, a prioritised list of issues…Meta Tag CheckerSee exactly how Google is likely to display your page: title and description measured in pixels, desktop…Heading CheckerVisualise the heading outline of any page. Find missing or duplicate H1s, skipped levels and empty…Image Alt CheckerAudit every image on a page in one table: alt text status, file size, width/height attributes, format and…Keyword Density CheckerEnter a URL and the keyword it should rank for. See where the keyword appears, how often, which phrases…Open Graph CheckerPreview how your link will look when shared on Facebook, LinkedIn, X and Slack. We flag missing tags, test…Page Speed TestRun Google Lighthouse on any URL for mobile or desktop. See performance, accessibility, best-practices and…Security Headers CheckerGrade a site’s HTTP security headers from A+ to F, see which are missing and why they matter, and copy…
JSON & Data Tools
All 7 json toolsJSON FormatterPaste JSON to pretty-print, minify or validate it. Errors are pinpointed to the exact line and column with…JSON to YAMLPaste JSON and get clean YAML for Kubernetes manifests, Docker Compose, GitHub Actions or any config file.…YAML to JSONPaste YAML — a Compose file, Kubernetes manifest or CI config — and get formatted JSON. Syntax errors are…JSON to CSVTurn a JSON array into a spreadsheet-ready CSV. Nested objects are flattened into columns like…CSV to JSONPaste CSV or TSV and get a JSON array of objects. Quoted fields, embedded line breaks and…JSON to TypeScriptPaste a JSON sample — an API response, a config — and get ready-to-use TypeScript interfaces with nested…JSON to Markdown TableTurn API responses or LLM-generated JSON arrays into a clean, aligned Markdown table for READMEs, docs and…
Encoders & Decoders
All 7 encoding toolsBase64 Encode / DecodeConvert text to Base64 and back with full UTF-8 support (accents, emoji), switch to URL-safe Base64, or…URL Encode / DecodePercent-encode text for safe use in URLs, decode encoded strings back to readable text, and break any URL…JWT DecoderPaste a JSON Web Token to inspect its header and payload, check when it expires and verify its signature.…Hash GeneratorCompute MD5 and SHA hashes of any text or file instantly, create HMAC signatures, and paste an expected…UUID GeneratorCreate cryptographically random UUIDs (v4) or sortable, timestamp-based UUIDs (v7) in bulk, then copy or…Unix Timestamp ConverterSee the current Unix time live, convert any epoch timestamp (seconds, milliseconds, micro- or nanoseconds)…HTML Entity EncoderEscape < > & " so text is safe to show in HTML, convert accents and symbols to named or numeric entities,…
Code Tools
All 12 code toolsHTML FormatterPaste minified or messy markup and get clean, consistently indented HTML — including embedded <style> and…CSS FormatterTurn a minified stylesheet into readable CSS with one property per line and properly nested @media blocks.…JavaScript FormatterUnminify and pretty-print JavaScript, JSON or JSX with your preferred indentation and brace style — or…CSS MinifierPaste a stylesheet to shrink it instantly. You’ll see the original and minified size, the percentage saved…SQL FormatterPaste a query — or a whole migration — and get readable SQL with one clause per line, aligned joins and…Regex TesterType a pattern and watch matches highlight live in your test text. Inspect every capture group, try…Diff CheckerPaste an original and a changed version to see added, removed and modified lines side by side — with the…cURL to CodePaste a curl command — from API docs or “Copy as cURL” in your browser’s DevTools — and get ready-to-run…
CSS & Design Tools
All 9 css toolsCSS Gradient GeneratorDesign a gradient visually — drag colour stops, change the angle or type, start from a preset — and copy…Box Shadow GeneratorStack multiple shadow layers, tweak offsets, blur, spread and opacity on a live card, then copy the…Clamp CalculatorEnter a minimum and maximum size and the viewport range — get a zoom-friendly clamp() value with the maths…PX to REM ConverterConvert between pixels, rem and em with your own root font size — or paste a whole stylesheet and convert…SVG to JSX ConverterPaste an SVG from Figma, Illustrator or an icon set and get a ready-to-use React (JSX or TSX) component —…SVG to CSS ConverterPaste an SVG and get a compact, URL-encoded data URI plus ready-made background-image and recolourable…Glassmorphism GeneratorDesign a frosted-glass card with live sliders and copy cross-browser CSS — with the…Tailwind Arbitrary Value GeneratorPaste CSS and get Tailwind’s bracket syntax right the first time — spaces turned into underscores, type…
Color Tools
All 10 color toolsHEX to RGBA ConverterPaste a HEX code, drag the opacity slider and copy the exact CSS you need — legacy rgba(), modern rgb( /…CSS Variables to TailwindTurn your :root colour variables into a Tailwind theme in one paste — Tailwind v3 tailwind.config.js or v4…OKLCH Color ConverterExplore the perceptually uniform OKLCH colour space with live sliders, see whether a colour fits in sRGB,…Color Name FinderPaste a HEX code to get its closest human-readable name and clean token names for your CSS, SCSS,…Color MixerPick two colours and a number of steps to get evenly blended transition colours — perfect for gradients,…Tailwind Color GeneratorPaste one brand colour and get a balanced 11-step shade scale (50 to 950) built in OKLCH — with contrast…APCA Contrast CheckerCalculate the APCA lightness contrast (Lc) between text and background, see which uses it’s suitable for,…Color Blindness SimulatorUpload a screenshot or design and see it through eight types of colour vision deficiency side by side — or…
Image Tools
All 6 images toolsImage CompressorShrink photos and graphics by 50–90% without visible quality loss. Batch-compress, convert to WebP or…Image ResizerResize a photo to exact pixel dimensions or a percentage, crop it to fill a social-media size, or fit it…Image to Base64Turn a PNG, JPEG, SVG, WebP or GIF into a Base64 data URI with copy-ready CSS and HTML — or paste a Base64…Favicon GeneratorMake a complete favicon package from a logo, a letter or an emoji: a multi-size favicon.ico, Apple touch…OG Image GeneratorCreate a polished link-preview image for Facebook, LinkedIn, X, Slack and WhatsApp in seconds — pick a…QR Code GeneratorGenerate a QR code for a link, Wi-Fi login, contact card, email, phone number or SMS. Customise colours,…
Web & Network Tools
All 7 web toolsWhat Is My IPYour public IP address and everything your browser reveals to the websites you visit — user agent, screen,…User Agent ParserDecode any User-Agent string into browser, engine, operating system and device — and find out whether it…DNS LookupQuery all common DNS record types for a domain in one go, with TTLs, sorted MX records and an SPF/DMARC…SSL CheckerVerify an HTTPS certificate in seconds — see when it expires, who issued it, which hostnames it covers and…Website Down CheckerFind out in seconds whether a website is down for everyone or just for you — with status code, response…API TesterA lightweight Postman alternative in your browser: build an HTTP request, send it and inspect status,…HTTP Status CodesEvery standard HTTP response code explained in plain English, with when to use it and how it affects SEO.…
Calculators & Converters
All 6 calc toolsPercentage CalculatorSeven everyday percentage calculations on one page. Results update as you type, and each shows the formula…Date Difference CalculatorCount the days between two dates — including business days and a years/months/days breakdown — add or…Time Zone ConverterConvert any time between cities and time zones, see the current time everywhere, and find a meeting slot…Unit ConverterConvert between metric, imperial and technical units in ten categories — with a two-way converter and a…Aspect Ratio CalculatorResize images and videos without distortion: fill in a ratio and one side to get the other, or enter a…Number Base ConverterType a number in any base and see it in all the others instantly. Inspect signed 8–64-bit two’s…
Text Tools
All 9 text toolsSoft Hyphen GeneratorStop long words like “Versicherungsleistungen” from overflowing on mobile: insert invisible soft hyphens…Smart Quotes to Straight QuotesCode copied from Slack, Notion, Word or a blog won’t run? Typographic “smart quotes”, dashes and…Markdown Task List ConverterPaste a plain list, bullet points or half-finished checklist and get clean - [ ] task lists for GitHub,…Case ConverterPaste any text and convert it between 11 letter cases — from Title Case for headlines to camelCase and…Word CounterPaste or type your text to count words and characters live — plus reading and speaking time, keyword…Slug GeneratorConvert any title into a clean, lowercase URL slug — with proper transliteration of accents, umlauts and…Lorem Ipsum GeneratorCreate placeholder text for mock-ups and layouts in seconds — classic Lorem Ipsum or readable English…Password GeneratorCreate strong, truly random passwords or easy-to-type passphrases. Generated locally with your browser’s…