Web & SEO

Web and SEO tools

Every web tool on OpenTools. Metadata, URLs, CSS, HTML and accessibility checks, run in your browser with no page ever uploaded.

All 48 of them are listed below. Each one runs inside this tab, so nothing you open or type is uploaded — see the proof.

• Accessibility contrast checkerCalculate WCAG contrast ratio and AA/AAA text thresholds for two hex colors.
• ARIA label checklistFlag common supplied-HTML controls that lack visible text or accessible naming attributes.
• Aspect-ratio calculatorReduce a width:height ratio and calculate a missing dimension.
• Browser compatibility checklistCreate a review checklist for a selected browser feature; this is not live compatibility data.
• Canonical URL builderNormalize an absolute URL and generate an escaped canonical link tag.
• CSS border-radius generatorSet a pixel radius for each corner and get the border-radius shorthand back in top-left, top-right, bottom-right, bottom-left order. Negatives are refused.
• CSS clamp calculatorGenerate a linear fluid clamp() expression between two viewport widths.
• CSS clip-path generatorGenerate a polygon() declaration from validated percentage coordinate pairs.
• CSS flexbox generatorPick a direction, a justify-content and align-items value, and a pixel gap, then copy the matching flex container block without recalling the property names.
• CSS glassmorphism & backdrop-filter generatorGenerate modern frosted glass CSS effects with backdrop blur, specular border highlights, and surface opacity.
• CSS gradient generatorGenerate linear-gradient CSS from validated angle and color stops.
• CSS Gradient Studio & SVG generatorGenerate modern linear, radial, and conic CSS gradients with multi-color stops, angle controls, Tailwind CSS classes, and SVG defs.
• CSS grid generatorGenerate a responsive grid declaration from columns, gap, and minimum width.
• CSS keyframe animation & physics generatorGenerate optimized pure CSS keyframe animations (pulse, shake, float, bounce, spin, fade-slide, shimmer) with custom easing curves and GPU acceleration.
• CSS neumorphism & soft-shadow generatorCalculate dual light and dark physics-based box shadows for soft UI buttons, cards, and inset surfaces.
• CSS shadow generatorGenerate a CSS box-shadow declaration from numeric controls.
• Domain name generatorGenerate deterministic domain candidates from comma-separated words; availability is not checked.
• Domain typo generatorGenerate bounded omission, transposition, and adjacent-key typo candidates for defensive review.
• Favicon & app icon HTML snippet generatorGenerate production-ready HTML <link> tags and web app manifest configurations for modern browsers and mobile devices.
• Favicon inspectorExtract icon link declarations from supplied HTML; no remote page is fetched.
• File to HTML converterTurn images into email-ready HTML with the images packaged alongside it, or into one standalone web page.
• Heading structure checkerList headings and flag level skips in supplied HTML source.
• Hreflang generatorGenerate alternate-language link tags from locale and URL pairs.
• HTML head inspectorInventory title, meta, and link elements from supplied HTML; this is not a browser render.
• HTML table generatorConvert tab-separated rows to an escaped HTML table; first row becomes the header.
• Keyword density analyzerCount exact case-insensitive phrase occurrences and percentage of word starts.
• Link extractorExtract quoted href attributes from supplied HTML and resolve them against a base URL.
• Meta tag generatorGenerate an escaped title, description, robots, and canonical head block.
• Open Graph generatorGenerate escaped Open Graph tags for a share preview.
• Query string builderBuild an encoded query string from key=value lines.
• Query string parserParse a query string and preserve repeated keys as arrays.
• Redirect chain plannerInspect source→destination pairs for chains, loops, and duplicate sources.
• Responsive breakpoint testerClassify a supplied viewport width against editable ascending breakpoints.
• Robots.txt generatorCreate a small robots.txt policy from user-agent and path rules.
• Robots.txt testerEvaluate Allow/Disallow path rules using longest matching rule; wildcards are not interpreted.
• Schema markup generatorGenerate a minimal JSON-LD WebSite, Organization, or WebPage object.
• Schema markup validatorValidate JSON syntax and the required JSON-LD @context and @type fields.
• SERP snippet previewCreate a text preview with transparent title and description character counts.
• Sitemap generatorTurn absolute HTTP(S) URLs into an escaped sitemap XML document.
• Sitemap viewerExtract and decode <loc> values from sitemap XML without making requests.
• SVG optimizer & cleanerClean and optimize SVG code by stripping comments, editor metadata, redundant attributes, and rounding coordinates.
• Text to HTML linkCreate an escaped anchor element from label, absolute URL, and target preference.
• Twitter card generatorGenerate X/Twitter card tags without fetching a page.
• URL normalizerLowercase host, remove fragments/default ports, sort parameters, and normalize the path.
• UTM builderAdd source, medium, campaign, term, and content parameters to an absolute URL.
• UTM parserPaste a campaign web address and read back its utm_source, utm_medium, utm_campaign, utm_term and utm_content values. HTTP and HTTPS addresses only.
• Viewport size calculatorConvert vw/vh percentages to pixels for a specified viewport.
• Web app manifest generatorGenerate a minimal standards-shaped web app manifest JSON file.