WebDev
Free tools for building, checking and launching websites: tidy and minify code, generate HTML, security headers and structured data, preview your pages in search and social, and find a domain name. Learn more
Browser Feature Detector
Test which web APIs and CSS features your browser supports right now.
Card Style Generator
Design a card's colours, border, radius, shadow and hover effect.
Common Breakpoint Reference
Bootstrap, Tailwind and device breakpoints, with your current width highlighted.
Content Security Policy (CSP) Builder
Build a Content-Security-Policy header with warnings for risky settings.
Cookie String Builder & Parser
Build a correct Set-Cookie string, or decode a Cookie header.
CSS File Joiner
Combine CSS files in your chosen order and safely remove overridden rules.
CSS File Splitter
Split a large stylesheet into smaller files without breaking the cascade.
CSS Selector Tester
Test a CSS selector against sample HTML, with specificity and highlights.
cURL Command Builder
Build a correctly quoted curl command for bash, PowerShell or Windows.
Domain Hack Generator
Find domain hacks like fami.ly across every country-code ending.
Domain Name Generator
Generate brandable domain name ideas from one or two keywords.
Domain Portfolio Renewal Tracker
Track your domains' renewal dates and costs, with due-soon alerts and CSV export.
Domain Syntax Validator
Check a domain against DNS naming rules, including international names.
Domain-to-Email Pattern Generator
See the email address patterns a company is most likely to use.
Favicon & Tab Title Preview Mockup
Preview your favicon and title in light and dark browser tabs, bookmarks and search results.
Google SERP Snippet Previewer
Preview your title and description in Google results on desktop and mobile.
HTML Boilerplate Generator
Generate a clean, valid HTML5 starter page with the extras you choose.
HTML Entity Encoder / Decoder
Encode special characters as HTML entities, or decode any named entity.
HTML Form Builder
Build an accessible HTML form with a live preview.
HTML Formatter
Pretty-print messy or minified HTML with proper indentation.
HTML Minifier
Shrink HTML by removing comments and extra whitespace safely.
HTML Table Generator
Build an accessible HTML table, or paste cells from a spreadsheet.
HTML Table of Contents Generator
Generate a nested table of contents and heading ids from your HTML.
HTML to Markdown Converter
Convert HTML to clean Markdown, including tables, lists and code.
HTTP Security Headers Generator
Generate HSTS, X-Frame-Options and other security headers for any server.
iframe Embed Code Generator
Turn a YouTube, Vimeo, Spotify or Maps link into responsive embed code.
JavaScript Formatter
Pretty-print messy or minified JavaScript with consistent indentation.
JS Minifier
Shrink JavaScript by stripping comments and whitespace safely.
JSON-LD Structured Data Generator
Generate schema.org JSON-LD for articles, products, FAQs and more.
Keyword Combination Domain Idea Tool
Combine two word lists into every domain name idea, in either order.
Nginx Config Snippet Generator
Generate nginx blocks for HTTPS, www redirects, caching and proxies.
package.json Generator
Build a valid package.json, with npm naming and version checks.
Robots Meta Tag Builder
Build a robots meta tag or X-Robots-Tag header for any search engine.
Service Worker Boilerplate Generator
Generate a safe, working service worker with an offline page.
Social Share Card Previewer
Preview your link on X, Facebook, LinkedIn and Discord, and get the tags.
Subdomain Naming Convention Generator
Get conventional subdomain names for your blog, shop, API and more.
TLD Reference Guide
Search 60 domain endings, what each is for and who can register it.
Trademark Clash Self-Check Checklist
Ten checks with direct links to trade mark registers before you commit to a name.
User-Agent String Parser
Break down any User-Agent into browser, OS, engine and device.
Viewport & Device Pixel Ratio Reporter
See your viewport size, pixel ratio and media-query values live.
Web App Manifest Generator
Build a PWA manifest.json with install checks and maskable icons.
WHOIS Privacy Decision Helper
Find out whether paying for WHOIS privacy is worth it for your domain.
Free web development tools that run in your browser
Whether you're building a site from scratch or tidying up one that's already live, these tools handle the fiddly jobs that slow you down. Start a page with the HTML Boilerplate Generator, build accessible markup with the HTML Form Builder and HTML Table Generator, and tidy code with the HTML Formatter and JavaScript Formatter. When you're ready to ship, the HTML Minifier and JS Minifier shrink your files without breaking code that leaves out semicolons, and the CSS File Joiner merges stylesheets while removing only rules that can never apply.
For search and sharing, the Google SERP Snippet Previewer measures your title in pixels the way Google does, the Social Share Card Previewer shows your link on X, Facebook, LinkedIn and Discord, and the JSON-LD Generator writes structured data that's safe to paste. Lock your site down with the CSP Builder and HTTP Security Headers Generator, which warn about risky settings and output ready-made snippets for nginx, Apache, IIS and Netlify. There are generators for service workers, web app manifests and package.json files, plus a cURL Command Builder that quotes correctly for bash, PowerShell or the Windows command prompt.
Choosing a name? The Domain Name Generator, Domain Hack Generator and Keyword Combination tool produce ideas to check with a registrar, the TLD Reference Guide explains who can register each ending, and the Trademark Clash Self-Check links straight to the UK, EU and US registers. Everything runs on your own device, so your code and plans are never uploaded.
Questions and answers
- What's the difference between the CSP Builder and the HTTP Security Headers Generator?
- The CSP Builder writes one header, Content-Security-Policy, which lists exactly where your pages may load scripts, styles, images and other files from. It's the strongest protection against cross-site scripting but needs tailoring to each site. The HTTP Security Headers Generator covers the simpler headers that suit almost any site, such as HSTS (always use HTTPS), X-Frame-Options (no framing by other sites) and Referrer-Policy. Most sites benefit from both.
- Should I use the formatters or the minifiers?
- Use them at opposite ends of the job. The HTML Formatter and JavaScript Formatter add indentation and line breaks so code is easy to read and edit, which helps when you've been handed minified code. The HTML Minifier and JS Minifier strip comments and spare whitespace to make files smaller for your live site. Keep your readable source and minify a copy for publishing, because minified code is hard to edit.
- Is the CSS File Joiner the reverse of the CSS File Splitter?
- Broadly, yes. The Joiner combines several stylesheets into one, in the order you choose, and removes only declarations that a later identical selector overrides, so nothing that affects your page is lost. The Splitter breaks one large stylesheet into consecutive parts that keep the cascade intact when loaded in order, or groups rules by selector type for review. Splitting by type changes the rule order, so check the result before using it.
- Do the domain tools check whether a name is available?
- No. The Domain Name Generator, Domain Hack Generator and Keyword Combination tool produce ideas without contacting anyone, so nothing you type reveals your plans to a registrar. Copy the ideas you like into a registrar's search to check availability. The Domain Syntax Validator checks that a name follows DNS rules, and the TLD Reference Guide tells you who is allowed to register each ending.
- Which tools show results for my own browser rather than for code I paste?
- The Browser Feature Detector, Viewport & Device Pixel Ratio Reporter and Common Breakpoint Reference all read the browser you're using right now, so open them on different phones, tablets and browsers to compare. The User-Agent String Parser starts with your own browser's details too, but you can paste any other User-Agent, such as one from your server logs, to identify it.