Free Web Tools

Browser-based tools for accessibility, SEO, and web quality. All processing happens locally - no data is sent to any server.

Color Contrast Checker

Check foreground/background color contrast ratios against WCAG 2.2 AA and AAA requirements. Instant pass/fail for normal and large text.

Open Graph Preview

Preview how your page appears on Facebook, Twitter/X, and Google search results. Paste your HTML to see OG, Twitter Card, and SERP previews.

Meta Tag Checker

Analyze your page meta tags for SEO completeness. Checks title, description, OG tags, Twitter cards, canonical URL, viewport, and more.

WCAG 2.2 Checklist

Interactive WCAG 2.2 Level AA checklist. Track your progress across all success criteria with explanations and techniques for each.

Alt Text Checker

Analyze images in your HTML for missing, empty, or decorative alt text. Identifies accessibility issues with image descriptions.

Visualize and validate your HTML heading structure (H1-H6). Detect skipped heading levels, missing H1 tags, multiple H1s, and incorrect nesting order. Paste any HTML to get an instant hierarchy report.

Color Palette Contrast Matrix

Check contrast ratios between all color combinations in your palette. Generates an NxN matrix showing WCAG AA/AAA pass/fail for every pair.

Robots.txt Tester

Test whether a URL path is allowed or blocked by your robots.txt rules. Validates syntax and checks against specific user agents.

Dark Mode Contrast Checker

Check color contrast ratios specifically for dark mode designs. Includes common dark theme presets and WCAG pass/fail indicators.

JSON-LD Schema Validator

Validate your JSON-LD structured data against schema.org specifications. Checks required properties, types, and common errors.

Sitemap Validator

Validate your XML sitemap structure, URL formatting, and required elements. Detects duplicate URLs, missing namespaces, invalid priority values, and checks lastmod and changefreq tags.

Favicon Checker

Check your HTML for favicon and icon declarations. Validates icon sizes, formats, apple-touch-icon, and manifest references.

Word Count & Reading Time

Count words, characters, sentences, and paragraphs in your text. Calculates estimated reading time based on average reading speed.

Lorem Ipsum Generator

Generate lorem ipsum placeholder text in paragraphs or words. Quickly create dummy content for mockups and wireframes.

Text Case Converter

Convert text between UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case instantly.

Base64 Encoder / Decoder

Encode text to Base64 or decode Base64 strings back to plain text. Useful for data encoding, APIs, and debugging.

URL Encoder / Decoder

Encode special characters in URLs using percent encoding, or decode percent-encoded URLs back to readable text.

HTML Entity Encoder / Decoder

Encode HTML special characters to entities (&, <, >) or decode HTML entities back to readable characters.

JSON Formatter & Validator

Format and validate JSON with 2-space indentation. Instantly spots syntax errors and shows line count and file size.

Regex Pattern Tester

Test regular expression patterns against sample text. Shows all matches with their positions and values.

Text Diff Checker

Compare two blocks of text and highlight differences line by line. Shows added lines in green and removed lines in red.

Password Strength Checker

Analyze password strength with a 0-4 score. Checks length, uppercase, lowercase, numbers, special characters, and common passwords.

Text to URL Slug

Convert any text into a clean, URL-friendly slug. Removes special characters, replaces spaces with hyphens, and lowercases everything.

UUID Generator

Generate cryptographically random UUID v4 values instantly. Generate multiple UUIDs at once with one-click copy.

Character Counter

Count characters, words, and lines in your text. Shows remaining characters for Twitter/X (280), SMS (160), and meta descriptions (160).

SEO Title Length Checker

Check if your page title is the optimal length for search engines (50-60 characters). Includes a live SERP preview card.

Meta Description Length Checker

Check if your meta description is the optimal length (120-160 characters) for search results. Includes a SERP snippet preview.

CSV to JSON Converter

Convert CSV data to formatted JSON arrays. Uses the first row as headers and outputs a clean JSON array of objects.

JSON to CSV Converter

Convert a JSON array of objects to CSV format. Automatically generates headers from object keys.

Whitespace Cleaner

Clean up messy text by removing extra spaces, trimming lines, and eliminating blank lines. Shows before and after character counts.

Readability Score

Calculate the Flesch Reading Ease score and grade level for any text. Shows reading difficulty label, avg sentence length, and syllables per word.

Markdown Previewer

Write Markdown and see the rendered HTML preview side by side. Supports headers, bold, italic, code blocks, lists, links, and blockquotes.

Link Text Analyzer

Find vague, generic, or empty link text in your HTML such as "click here", "read more", or "here". Improves accessibility and SEO.

Form Accessibility Checker

Check all form inputs for associated labels, aria-label, or aria-labelledby. Ensures your forms are accessible to screen reader users.

Duplicate ID Finder

Find duplicate id attributes in your HTML. Duplicate IDs break accessibility, CSS targeting, and JavaScript selectors.

ARIA Attribute Checker

Validate ARIA roles, states, and properties in your HTML. Flags misuse of aria-hidden, invalid roles, and empty aria-labels.

Table Accessibility Checker

Check HTML tables for accessibility: captions, th scope attributes, thead/tbody structure, and layout table detection.

Iframe Title Checker

Verify that all iframes in your HTML have descriptive title attributes. Missing iframe titles are a common WCAG accessibility failure.

Deprecated HTML Detector

Find obsolete HTML tags and attributes that should not be used in HTML5. Flags elements like center, font, marquee, and deprecated attributes.

HTML Language Attribute Checker

Verify that your HTML document has a valid lang attribute on the html element. Essential for screen readers and international SEO.

Viewport Meta Tag Checker

Check your viewport meta tag for mobile optimization. Detects missing width=device-width, missing initial-scale, and zoom-disabling configurations.

Input Field Checker

Analyze HTML form inputs for valid type attributes, autocomplete attributes, and required/aria-required consistency.

Canonical URL Extractor

Extract and compare canonical URLs, og:url, and other URL meta tags from your HTML. Flags mismatches that can cause SEO issues.

Hreflang Tag Checker

Extract and validate hreflang tags for international SEO. Checks for x-default, self-referencing tags, and language code validity.

Structured Data Extractor

Extract and display all JSON-LD structured data blocks from your HTML. Parses each block and highlights schema types.

Script Tag Analyzer

Analyze all script tags in your HTML. Identifies render-blocking scripts, inline vs external scripts, and async/defer status.

Resource Hints Checker

Check resource hint link tags in your HTML: preload, prefetch, preconnect, and dns-prefetch. Flags preloads missing the as attribute.

CSS Class Extractor

Extract all unique CSS class names from your HTML. Shows frequency counts, alphabetical sorting, and easy copy options.

CSS Color Converter

Convert CSS colors between HEX, RGB, RGBA, HSL, HSLA, and HSV formats. Supports named colors, hex shorthand, and all standard CSS color formats.

Font Size Calculator

Calculate font sizes in em, rem, percentage, and vw from pixel values. Instantly convert between CSS font size units.

Line Height Calculator

Calculate actual line height in pixels from unitless, pixel, or percentage values. Includes readability recommendations.

CSS Specificity Calculator

Calculate CSS selector specificity as [a, b, c] values. Compare multiple selectors to see which one wins.

CSS Gradient Generator

Create linear and radial CSS gradients with a live preview. Adjust colors, angle, and gradient type, then copy the CSS code.

CSS Box Shadow Generator

Generate CSS box-shadow values with live preview. Control x/y offset, blur, spread, color, and inset. Supports multiple shadows.

Border Radius Previewer

Set individual corner radius values and preview the result live. Generates the CSS border-radius property value.

Aspect Ratio Calculator

Calculate missing width or height from an aspect ratio. Supports common ratios like 16:9, 4:3, and 1:1. Shows the CSS aspect-ratio value.

Viewport Units Calculator

Calculate CSS viewport unit values in pixels. Enter a viewport size to see 1vw, 1vh, 1vmin, and 1vmax in pixels, and convert between units.

CSS Clamp() Calculator

Generate CSS clamp() values for fluid typography and spacing. Enter min/max sizes and viewport widths to get the perfect clamp() expression.

Modular Type Scale

Generate a modular type scale from a base size and ratio (Major Third, Perfect Fourth, Golden Ratio, etc.). Shows sizes in px, em, and rem.

Spacing Scale Generator

Generate a spacing scale from a base size and multiplier. Outputs px and rem values as a CSS custom properties block.

Z-Index Reference & Manager

Interactive reference for CSS z-index values. Shows common layering conventions and helps you find the right z-index for your element.

CSS Custom Properties Extractor

Extract all CSS custom properties (--variable-name) from HTML or CSS. Shows names, values, and generates a CSS :root block for easy copying.

FAQ Schema Builder

Build FAQPage structured data JSON-LD from a dynamic list of question and answer pairs. Copy the script tag directly into your page head.

Article Schema Builder

Generate Article structured data JSON-LD for blog posts and news articles. Fill in the form and copy the schema script tag.

Breadcrumb Schema Builder

Build BreadcrumbList structured data from a dynamic list of breadcrumb name and URL pairs. Helps Google display breadcrumb trails in search results.

Product Schema Builder

Generate Product structured data for e-commerce pages. Includes price, availability, brand, SKU, and aggregate rating fields.

Organization Schema Builder

Generate Organization structured data JSON-LD. Includes name, URL, logo, contact info, address, and social profile URLs.

Local Business Schema Builder

Build LocalBusiness structured data for local SEO. Includes business type, address, phone, opening hours, and price range.

Event Schema Builder

Generate Event structured data JSON-LD for concerts, webinars, and other events. Includes location, date/time, organizer, and ticket URL.

Review Schema Builder

Generate Review and AggregateRating structured data JSON-LD. Shows star ratings in Google search results.

Keyword Density Analyzer

Analyze keyword frequency and density in your content. Shows density percentage, top words, and recommendations for optimal keyword usage.

Image SEO Checker

Check all images in your HTML for SEO and accessibility issues: alt text, src filenames, loading attribute, and width/height attributes.

Internal Link Checker

Categorize all links in your HTML as internal or external. Flags duplicate links, anchor-only links, and basic link structure issues.

Page Speed Checklist

Interactive checklist of page speed best practices across images, JavaScript, CSS, fonts, and server configuration. Track your progress.

On-Page SEO Checklist

Interactive on-page SEO checklist covering technical SEO, content optimization, schema markup, and social meta tags. Track your progress.

Core Web Vitals Reference

Interactive reference for LCP, INP, CLS, FCP, and TTFB. Enter your metric values to see if they pass Google threshold requirements.

Canonical vs URL Mismatch Checker

Compare a page URL against its canonical URL to detect protocol mismatches, domain differences, case issues, and trailing slash inconsistencies.

Redirect Chain Visualizer

Visualize URL redirect chains and flag long chains (3+ hops), mixed HTTP/HTTPS redirects, and other redirect issues.

Content Security Policy Analyzer

Parse and analyze a Content Security Policy header. Flags dangerous values like unsafe-inline, unsafe-eval, and wildcards.

Security Headers Checker

Check HTTP response headers for security best practices. Verifies HSTS, X-Content-Type-Options, X-Frame-Options, CSP, and more.

CORS Header Analyzer

Analyze CORS-related HTTP headers for misconfigurations. Flags wildcard origins with credentials, and explains each directive.

Cookie Attribute Checker

Parse Set-Cookie headers and check each cookie for security attributes: Secure, HttpOnly, SameSite, and expiration settings.

HTTP Status Codes Reference

Complete searchable reference for all HTTP status codes (1xx through 5xx). Includes code, name, description, and common use cases.

ARIA Roles Reference

Searchable reference for all WAI-ARIA roles: landmark, widget, document structure, and abstract roles with descriptions.

HTML Elements Reference

Searchable reference for all HTML elements with display type, semantic flag, and descriptions. Organized by category.

CSS Units Reference

Complete reference for all CSS units (px, em, rem, vw, vh, %, pt, and more). Includes type, description, best use cases, and interactive converter.

MIME Types Reference

Searchable reference for common MIME types organized by category: text, image, audio, video, application, and font types.

CSS Color Names Reference

Browse all 147 CSS named colors as swatches. Search by name or hex value, and click any color to copy its hex code.

WCAG 2.2 Success Criteria Reference

Complete searchable reference for all WCAG 2.2 success criteria. Filter by conformance level (A/AA/AAA) and search by keyword.

Unicode Character Lookup

Look up Unicode characters by typing or pasting them, or by entering a code point. Shows HTML entity, CSS escape, decimal, and hex values.

HTML5 Semantic Elements Guide

Interactive reference for HTML5 semantic elements including header, nav, main, article, section, aside, and footer with usage examples.

CSS/HTML Browser Support Reference

Browser support table for modern CSS and HTML features: CSS Grid, Flexbox, Container Queries, :has(), CSS Clamp, and more.

Image Format Analyzer

Analyze image formats in your HTML. Flags JPEG/PNG images that should be WebP or AVIF, GIFs that should be video, and provides optimization recommendations.

Web Font Declaration Checker

Check web font loading in your HTML. Finds font links, @font-face declarations, and flags missing font-display: swap and preload hints.

Third-Party Script Analyzer

Categorize external scripts in your HTML by type: analytics, advertising, support, social, and other. Checks async/defer status.

Render-Blocking Resources Checker

Find render-blocking scripts and stylesheets in your HTML. Provides specific recommendations to fix each blocking resource.

Cache-Control Header Analyzer

Parse and explain every directive in a Cache-Control header. Shows what browsers and CDNs will do with the caching strategy.

Performance Budget Calculator

Calculate your web page performance budget based on target load time and connection speed. Shows recommended byte limits per resource type.

Lazy Loading Checker

Check images and iframes in your HTML for the loading="lazy" attribute. Flags elements missing lazy loading to improve initial page load.

Preload & Resource Hints Analyzer

Analyze all preload link tags for correct as attribute, crossorigin for fonts, and check for missing preloads on critical resources.

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