Aspect Ratio Calculator
Given any two of width, height, or a ratio (e.g. 16:9), calculate the missing dimension.
Dev Tools
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HTTP Request Builder
Send any HTTP method with custom headers and body; inspect the full response.
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Base64
Encode UTF-8 text as Base64, or decode Base64 to UTF-8 text.
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URL Encoder
Percent-encode arbitrary text for safe inclusion in URLs, or decode percent-encoded text.
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HTML Entities
Escape HTML special characters as entities (& < > "), or decode entities to plain text.
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JSON Formatter
Pretty-print, minify, or sort-key JSON.
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HTTP Headers
Fetch a URL and inspect response headers, status code, and redirect chain.
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Text Diff
Compute a unified diff between two blocks of text (line-based).
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CORS Tester
Send a CORS preflight + GET to a URL and inspect Access-Control-* headers; flags common misconfigurations.
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URL Parser / Builder
Break a URL into its components (scheme, host, port, path, query params, fragment) or assemble one from parts.
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Regex Tester
Test a regular expression against a string — shows all matches, captured groups, and highlights matches inline.
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Cron Expression Parser
Translate a cron expression into next 8 scheduled run times (UTC). Supports 5-field and 6-field (with seconds) syntax.
Designer Tools
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Color Converter
Convert between HEX, RGB, and HSL color notations with a preview swatch.
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Meta Tag Preview
Fetch a URL and preview how it appears as a Google result, Twitter card, and Open Graph share.
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Aspect Ratio Calculator
Given width, height, or a W:H ratio, calculate the missing dimension and show the simplified ratio.
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Image to Base64
Fetch an image URL and convert it to a Base64 data URI for embedding directly in CSS or HTML.
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Site Color Palette
Load a URL in headless Chromium, extract every computed CSS color, and list them as a sortable palette with swatches.
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Tech Stack Detector
Load a URL in headless Chromium and identify the CSS frameworks, JS frameworks, analytics, CDNs, CMS, and hosting platform used to build the site.