Seo
AI Crawler robots.txt Builder
Build a robots.txt policy for AI crawlers. Choose from open, selective, or strict presets and block specific AI training bots while allowing search engines.
Tools
Small web tools that run in your browser
Generate tags, clean launch details, and prepare static pages without accounts, uploads, or busywork.
SEO Tools
Small browser tools for metadata, indexing, canonical URLs, social previews, and static site launch checks.
Open tool
Seo
Hreflang Sitemap Builder
Build XML sitemap entries with hreflang alternates for multilingual pages. Validate reciprocal links between language versions.
Seo
llms.txt Validator
Validate llms.txt files against the specification. Check H1 headings, blockquote summaries, section structure, and Markdown link formatting.
Seo
OpenSearch Description Generator
Generate an OpenSearch description XML file and HTML link tag so browsers can add your site's search as a search engine.
Seo
Static Site SEO Checklist Generator
Generate a practical SEO checklist for static websites before launch.
Seo
JSON-LD Starter Builder
Generate starter JSON-LD for WebSite, Organization, Article, FAQ, or BreadcrumbList.
Seo
Viewport Meta Tag Generator
Generate a complete set of viewport meta tags plus theme-color and Apple touch icon links.
Seo
Static Sitemap XML Builder
Paste a list of URLs and get a complete sitemap.xml file for static hosting and GitHub Pages.
Seo
Speculation Rules Generator
Generate Speculation Rules JSON for prerendering and prefetching pages in Chrome and Edge.
Seo
Permissions-Policy Header Generator
Generate a Permissions-Policy HTTP header to control browser feature access across your site.
Seo
CSP Starter Policy Generator for Static Sites
Generate a Content-Security-Policy header for static sites with CDN, analytics, font, and embed options.
Seo
Markdown Front Matter Generator
Generate YAML front matter blocks for Jekyll, Hugo, Astro, 11ty, and other static site generators.
Seo
RSS Feed Starter Generator
Generate a complete RSS 2.0 XML feed for your static blog from a list of posts.
Seo
JSON Feed Starter Generator
Generate a JSON Feed file for your static blog as a modern, machine-readable alternative to RSS.
Seo
Referrer Policy Tag Generator
Generate a Referrer-Policy header or meta tag to control how much referrer information is sent with outbound links.
Seo
X-Robots-Tag Header Generator
Generate X-Robots-Tag HTTP headers and robots meta tags for non-HTML files, PDFs, images, feeds, and HTML pages.
HTML Tools
Copy-paste helpers for cleaner HTML tags, head markup, snippets, and publishing workflows.
Html
ARIA Live Region Generator
Generate accessible ARIA live region HTML snippets with role, aria-live, aria-atomic, and aria-relevant attributes. Includes optional JavaScript update function.
Html
CSP Hash Generator
Generate CSP hash values for inline scripts and styles. Hash exact code content with SHA-256, SHA-384, or SHA-512 and get the matching CSP directive snippet.
Html
Customizable Select Generator
Generate CSS for customizable select elements using appearance: base-select, picker icons, checkmarks, and open/closed state styling.
Html
Declarative Shadow DOM Snippet Generator
Generate HTML snippets for Declarative Shadow DOM with scoped CSS, slots, open/closed mode, and server-rendering fallback content.
Html
HTML Invoker Command Generator
Generate declarative command buttons for dialogs, popovers, and disclosure elements using the Invoker Commands API. No JavaScript needed.
Html
HTML Sanitizer Config Builder
Generate Sanitizer API and DOMPurify allowlist configurations. Choose content-type presets or customize allowed tags and attributes for safe HTML rendering.
Html
SRI Hash Generator
Generate Subresource Integrity hashes for script and stylesheet files. Paste code, upload a local file, or reference a CDN URL and get the integrity attribute for your HTML tags.
Html
HTML Link Rel Generator
Generate link tags for preload, preconnect, dns-prefetch, canonical, and alternate URLs.
Html
Responsive Iframe Embed Generator
Generate responsive iframe embed markup for videos, maps, demos, and docs.
Html
HTML Heading Hierarchy Checker
Paste HTML and see the heading structure as a tree. Find skipped levels, missing h1 tags, and hierarchy problems.
Html
Reading Time Estimator
Paste text and get an estimated reading time based on word count and adjustable reading speed.
Html
HTML Entity Quick Reference
Search and copy common HTML entities including arrows, dashes, quotes, math symbols, and special characters.
Html
HTML Popover Generator
Generate native HTML popover markup using popovertarget and the Popover API without JavaScript.
Html
Iframe Sandbox & Allow Attribute Generator
Generate secure iframe markup with sandbox flags and allow permissions by embed type.
Html
Table of Contents Anchor Generator
Paste HTML headings and get a nested table of contents with anchor links for articles and documentation.
Html
Dialog Modal HTML Generator
Generate a native HTML dialog modal with open and close buttons using the dialog element.
Html
No-JS Redirect Page Generator
Generate a complete HTML redirect page using the meta refresh tag without JavaScript.
Html
Static 404 Page Template Generator
Generate a friendly 404 error page with navigation links for static websites and GitHub Pages.
Html
Accessible Skip Link Generator
Generate an accessible skip-to-main-content link with CSS for keyboard and screen reader navigation.
Html
HTML Landmark Checker
Paste HTML and check for ARIA landmark elements that help screen readers navigate the page structure.
Html
Input Attributes Generator
Generate HTML input elements with type-specific attributes for forms on static websites.
Html
Fetch Priority Attribute Generator
Generate fetchpriority attributes for images, scripts, and link tags to improve Core Web Vitals.
Html
Preload Tag Builder
Generate correct preload link tags for fonts, hero images, CSS, and scripts with the right as and crossorigin attributes.
Html
Modulepreload Tag Generator
Generate modulepreload link tags for ES module scripts in Vite, Astro, and modern static sites.
Html
Image Loading Attribute Builder
Build optimized img tags by combining loading, decoding, and fetchpriority for hero images, galleries, and article content.
Html
HTML Details Accordion Generator
Generate FAQ accordions and collapsible disclosure panels using the native details and summary elements without JavaScript.
Html
External Link Attribute Generator
Generate external link markup with the correct rel attributes for security, SEO, sponsored content, and user-generated content.
Html
HTML Script Loading Strategy Builder
Generate script tags with the right loading strategy -- normal, defer, async, or type module -- based on use case.
Html
Navigation API Router Snippet Generator
Generate JavaScript code for client-side routing using the Navigation API. Intercept navigations, match route patterns, and update content without full page reloads.
Html
Service Worker Module Template Generator
Generate an ES module service worker with configurable cache strategies, precache URL list, auto-activation, and offline fallback support.
Html
Trusted Types Policy Generator
Generate a Trusted Types policy with configurable createHTML/createScript/createScriptURL operations and matching Content-Security-Policy headers for Nginx and Apache.
Html
URLPattern Tester
Test URL patterns with named groups, wildcards, and regex constraints. Generate JavaScript URLPattern code and see live match results with extracted parameters for multiple test URLs.
Html
contenteditable plaintext-only Generator
Generate accessible contenteditable=plaintext-only HTML markup with placeholder styling, focus states, and ARIA attributes. Pasting rich text strips formatting automatically -- no JavaScript needed.
Html
Directory Upload Input Generator
Generate HTML input markup with the webkitdirectory attribute for folder selection, drag-and-drop zone, file list display with webkitRelativePath, and support for single-file, multiple-file, and directory modes.
Html
scrollend Event Snippet Generator
Generate JavaScript snippets using the scrollend event that fires when scrolling fully completes including momentum and inertia, with debounce comparison to show why native scrollend is more accurate.
Html
PerformanceObserver Snippet Generator
Generate JavaScript snippets using PerformanceObserver to monitor Core Web Vitals (LCP, INP, CLS, FID, FCP, TTFB) and other performance metrics in real-time with good/needs-improvement/poor threshold classifications.
Html
Uint8Array Base64/Hex Converter
Encode and decode Uint8Array data using native toBase64(), toHex(), fromBase64(), and fromHex() methods. No more manual btoa or charCodeAt loops.
Html
RegExp.escape() Helper
Escape special regex characters in user input using the native RegExp.escape() method. Generate safe dynamic regex patterns with comparison to old manual escaping.
Html
Intl.DurationFormat Generator
Format durations with locale-aware Intl.DurationFormat. Supports long, short, narrow, and digital styles in 6+ locales. No more moment-duration-format.
Html
Custom Highlight API Generator
Generate JavaScript and CSS snippets for the Custom Highlights API to style arbitrary text ranges without modifying the DOM. Uses CSS.highlights registry and ::highlight() pseudo-element for find-in-page, syntax highlighting, and search results.
Html
WebTransport URL Template Helper
Generate a JavaScript WebTransport connection snippet with URL template, bidirectional streams, and datagram support for low-latency client-server communication over HTTP/3 (QUIC).
Html
Interest Invoker Popover Generator
Generate declarative HTML popover markup using the interestfor invoker command for hover and focus-triggered tooltips without JavaScript.
Html
ARIA Notify Snippet Generator
Generate JavaScript snippets using the ARIA Notify API for programmatic screen reader announcements with aria-live fallback.
Html
JSON Formatter & Validator
Format, validate, minify, and tree-view JSON data. Detects trailing commas, shows error position with context. All processing happens in the browser -- no data sent anywhere.
Html
JSON to CSV Converter
Convert JSON arrays to CSV/TSV with configurable delimiter, optional header row, nested field flattening via dot notation, and download-ready output.
Html
YAML JSON Converter
Bidirectional YAML to JSON and JSON to YAML converter. Handles nested objects, arrays, and scalar values. Useful for config files, GitHub Actions, front matter, and Docker Compose.
Html
JSONPath Tester
Test JSONPath expressions against JSON data. Supports dot notation, bracket notation, wildcards, array indices, and filter expressions. Shows matched values with paths.
Html
JSON Schema Generator & Validator
Generate JSON Schema from sample JSON data, or validate JSON against an existing schema. Supports Draft 04/07/2020-12. Infers types, marks required fields, includes examples.
Html
Regex Tester and Debugger
Test regular expressions against text with match highlighting, capture groups, and replacement preview. All processing is local in the browser.
Html
JWT Decoder and Claims Inspector
Decode JWT tokens to inspect header, payload claims, and timestamps. All decoding happens locally 閳?no token is sent to any server.
Html
Base64 Encoder and Decoder
Encode text to Base64 or decode Base64 back to text. Supports URL-safe Base64 variant. All processing is local.
Html
URL Encoder and Decoder
Encode or decode URL-encoded strings. Supports both encodeURIComponent (full) and encodeURI (URL-safe) modes.
Html
Query String Parser and Builder
Parse URL query strings into key-value tables, or build query strings from parameters. Detects duplicates and sorts parameters.
Html
UUID Generator
Generate UUID v4 (random) or v7 (time-ordered) identifiers with configurable options
Html
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates with timezone support
Html
Cron Expression Builder
Build and understand cron schedule expressions with presets or custom fields
Html
Hash and HMAC Generator
Generate cryptographic hashes and HMAC JavaScript code using Web Crypto API
Html
Markdown Preview Editor
Split-screen Markdown editor with live GitHub-Flavored Markdown preview. Supports headings, bold/italic, links, code blocks, tables, and task lists.
Html
QR Code Generator
Generate QR codes as SVG for URLs, text, email, phone, and WiFi. Customizable colors, size, and includes SVG code output for use in HTML.
Html
Image Compressor and Converter
Compress and convert images locally using Canvas API. Resize by width/height, choose JPEG/PNG/WebP output, and adjust quality. No upload -- all processing is local.
CSS Tools
Practical CSS generators for responsive layouts, spacing, mobile polish, and everyday UI fixes.
Css
Container Query Units Calculator
Calculate clamp() values using container query units (cqi, cqw, cqb, cqmin, cqmax) for component-level responsive sizing.
Css
CSS Carousel Generator
Generate native CSS carousel markup with scroll-snap, scroll buttons, scroll markers, and accessible list structure. No JavaScript required.
Css
CSS Scroll-State Query Generator
Generate CSS scroll-state() container queries for styling snapped, stuck, or scrollable elements. Includes JavaScript fallback for cross-browser support.
Css
CSS Subgrid Layout Generator
Generate parent grid and child subgrid CSS. Create layouts where nested grid items align with the parent grid tracks.
Css
Focus Ring CSS Generator
Generate accessible :focus-visible outline or box-shadow focus ring CSS with contrast checking against background colors.
Css
CSS Safe Area Insets Generator
Generate CSS for safe-area insets on phones with notches and rounded corners.
Css
CSS Color Contrast Checker
Check the contrast ratio between two colors against WCAG accessibility standards.
Css
CSS Box Shadow Builder
Build box-shadow CSS visually by adjusting offset, blur, spread, and color.
Css
CSS Flexbox Generator
Generate flexbox container CSS and sample HTML by selecting flex direction, wrap, alignment, and justification.
Css
CSS Border Radius Builder
Set rounded corners individually for each corner and generate the border-radius CSS declaration.
Css
Touch Target Size Checker
Check interactive element dimensions against WCAG 2.2 Target Size (2.5.8) requirements. Get AA/AAA results with CSS fix recommendations.
Css
View Transition Builder
Generate View Transitions API CSS and JavaScript for smooth page and element transitions. Same-document (SPA) and cross-document (MPA) support with reduced-motion fallback.
Css
CSS Cascade Layer Planner
Plan @layer order and generate a CSS cascade layer structure with example rules.
Css
CSS Content Visibility Generator
Generate CSS for content-visibility and contain-intrinsic-size to speed up long pages.
Css
CSS Overscroll Behavior Generator
Generate overscroll-behavior CSS to control pull-to-refresh, scroll chaining, and bounce effects.
Css
CSS Scroll Snap Generator
Generate CSS scroll-snap rules for carousels, galleries, and horizontal scroll sections.
Css
Container Query Snippet Generator
Generate CSS container query rules for component-based responsive design.
Css
Aspect Ratio Placeholder Calculator
Calculate aspect-ratio CSS values and padding-bottom fallbacks to prevent Cumulative Layout Shift.
Css
Dynamic Viewport Units Generator
Generate CSS using dynamic viewport units (dvh, svh, lvh) with fallbacks for older browsers.
Css
CSS Logical Properties Converter
Convert physical CSS properties to logical properties for better right-to-left and writing-mode support.
Css
CSS Anchor Positioning Generator
Generate CSS anchor positioning rules for tooltips, dropdowns, and callouts aligned to trigger elements.
Css
Scroll-Driven Animation Generator
Generate CSS scroll-driven animations with animation-timeline for reading progress bars, reveal effects, and parallax.
Css
Discrete Transition Generator
Generate CSS for animating elements that enter or leave the page using transition-behavior, @starting-style, and overlay.
Css
CSS Light-Dark Function Generator
Generate CSS color-scheme and light-dark() function rules for basic dark mode without duplicate variables.
Css
CSS Color Mix Generator
Generate CSS color-mix() function calls for hover states, borders, backgrounds, and muted text from a base color.
Css
CSS Relative Color Syntax Generator
Generate CSS relative color syntax to create alpha, lighter, darker, and channel-adjusted variants from any base color.
Css
CSS Print Styles Generator
Generate a print stylesheet that hides navigation, shows link URLs, avoids page breaks in important blocks, and sets print margins.
Css
CSS contrast-color() Function Generator
Generate CSS contrast-color() expressions that automatically pick the color with the best contrast ratio from a candidate list. No JavaScript text-color switching needed.
Css
Typed CSS attr() Generator
Generate typed CSS attr() expressions that read HTML attribute values into any CSS property with proper type casting. Supports number, px, rem, em, color, deg, s, ms, url, and percentage types.
Css
CSS if() Function Builder
Build CSS if() conditionals using style(), media(), and supports() conditions for inline responsive values without @media or @container queries.
Css
CSS Sibling Index and Count Generator
Generate CSS using sibling-index() and sibling-count() to style elements by their DOM position among siblings without nth-child selectors.
Css
CSS progress() Function Calculator
Calculate CSS progress() function values that map an input value from one range to a 0-1 progress value for scroll-driven animations and value mapping.
Css
CSS Stretch Sizing Generator
Generate CSS using the stretch keyword for fill-available sizing in block, flex, grid, and absolutely positioned layouts.
Css
CSS text-indent hanging and each-line Builder
Build CSS text-indent values using the hanging and each-line keywords with fallback for older browsers. Generate reverse indentation for bibliographies and definition lists.
Css
CSS Font Relative Units Calculator
Calculate pixel equivalents for root-relative font units rcap, rch, rex, and ric compared to rem. Understand when to use each unit based on glyph measurements.
Css
CSS shape() Function Generator
Generate CSS shape() function values for clip-path and shape-outside with polygon, circle, ellipse, path, and rect types. Supports percentage coordinates, reference boxes, and animated transitions.
Css
CSS @scope Rule Builder
Generate CSS @scope at-rules that scope styles to a DOM subtree. Configure upper boundary (scope root) and optional lower boundary (scope limit) with lower specificity than unscoped styles.
Css
SVG Optimizer
Optimize SVG files by removing comments, metadata, editor data, and collapsing whitespace. Shows before/after size comparison. All local processing.
Css
SVG to CSS Data URI Converter
Convert SVG markup to CSS data URIs for background-image, img src, or raw data URI. URL-encoded and Base64 options with live preview.
Css
CSS Gradient Generator
Visual builder for linear, radial, and conic CSS gradients with live preview. Adjust angle, color stops, and positions. Copy clean CSS.
Css
CSS Filter Generator
Visual CSS filter editor with nine filter functions and live preview. Test on gradient swatch or optional image URL. Copy clean CSS output.
Css
CSS Text Shadow Generator
Build multi-layer CSS text shadows with neon, glow, 3D, and outline presets. Customize text, size, and up to three layers. Live preview.
Css
CSS Animation Keyframes Generator
Nine animation presets (fade, slide, scale, spin, pulse, bounce, shake) with customizable duration, easing, and iteration. Live preview with replay.
Css
CSS 3D Transform Generator
Visual 3D CSS transform builder with rotate, translate, scale, perspective, and origin controls. Live preview card shows depth in real time.
Image & Asset Tools
Local helpers for icons, image markup, asset paths, and static website files.
Assets
PWA Maskable Icon Safe Zone Generator
Upload an app icon and preview the PWA maskable safe zone with overlay. Export manifest-ready icon entries with correct purpose and size references.
Assets
Responsive Image Markup Generator
Generate img or picture markup with srcset, sizes, width, height, and alt text.
Assets
Web App Manifest Generator
Generate a site.webmanifest JSON file for PWA-ready static websites.
Assets
Web App Manifest Validator
Validate a web app manifest JSON against the W3C specification. Check required fields, icon sizes, start URL, scope, display mode, theme colors, and installability.
GitHub Pages Tools
Tools for custom domains, static publishing, launch checks, and GitHub Pages website maintenance.
Github Pages
Assetlinks & AASA Generator
Generate Android assetlinks.json and Apple App Site Association (AASA) files for Universal Links and Android App Links.
Github Pages
Cache-Control Header Builder
Build correct Cache-Control HTTP headers for static assets, HTML pages, feeds, and sensitive content.
Github Pages
COOP/COEP/CORP Header Builder
Build Cross-Origin isolation headers for SharedArrayBuffer, WebAssembly threads, and cross-origin security. Choose from presets with debugging checklists.
Github Pages
CORS Header Generator
Generate CORS HTTP headers for any origin, method, and credential configuration. Output in raw HTTP, Nginx, Apache, Express, or Cloudflare Workers format.
Github Pages
HTTP Header Parser & Explainer
Paste raw HTTP response headers and get a grouped, plain-English explanation of each header. Includes security advisories for missing security headers.
Github Pages
GitHub Pages CNAME Helper
Create the CNAME file content and DNS notes for a GitHub Pages custom domain.
Github Pages
Redirect Map Converter
Convert a CSV redirect map to Netlify _redirects, netlify.toml, Vercel vercel.json, Apache .htaccess, or Nginx config. Validate duplicates and redirect chains.
Github Pages
security.txt Generator & Validator
Generate and validate security.txt files per RFC 9116. Specify your contact, expiration, and optional fields, then get hosting guidance for GitHub Pages, Netlify, and Vercel.
Github Pages
GitHub Pages SPA 404 Helper
Generate a 404.html fallback for single-page apps on GitHub Pages.
Github Pages
VAPID Key Generator
Generate a VAPID key pair for Web Push notifications using the browser's Web Crypto API. Output ready-to-use keys for Node web-push, Firebase, and environment variables.
Github Pages
DNS Record Quick Reference
Enter a domain name and see example A, AAAA, CNAME, MX, and TXT records with setup notes.
Github Pages
GitHub Pages Workflow Generator
Generate a GitHub Actions workflow YAML to deploy a static site, Vite, or Astro project to GitHub Pages.
Github Pages
Reporting API Header Generator
Generate Report-To and Reporting-Endpoints HTTP headers for Nginx and Apache, plus CSP Reporting and Network Error Logging configuration.
Github Pages
Zstandard Compression Header Helper
Generate server configuration for Zstandard (zstd) compression with Content-Encoding headers, Accept-Encoding negotiation, and fallback chains for Nginx, Apache, Cloudflare, and Netlify.