Aspect Ratio Calculator

Send HTTP requests with custom method, headers, body, and authentication — inspect the full response.

Test any URL for CORS (Cross-Origin Resource Sharing) with a custom method, headers, and body — see exactly why a browser would allow or block the request.

Encode UTF-8 text as Base64, or decode Base64 to UTF-8 text.

Percent-encode arbitrary text for safe inclusion in URLs, or decode percent-encoded text.

Escape HTML special characters as entities (& < > "), or decode entities to plain text.

Pretty-print, minify, or sort-key JSON.

Fetch a URL and inspect response headers, status code, and redirect chain.

Compute a unified diff between two blocks of text (line-based).

Break a URL into its components (scheme, host, port, path, query params, fragment) or assemble one from parts.

Test a regular expression against a string — shows all matches, captured groups, and highlights matches inline.

Translate a cron expression into next 8 scheduled run times (UTC). Supports 5-field and 6-field (with seconds) syntax.

Load a URL in headless Chromium and identify the CSS frameworks, JS frameworks, analytics, CDNs, CMS, and hosting platform used to build the site.

Convert between HEX, RGB, and HSL color notations with a preview swatch.

Fetch a URL and preview how it appears as a Google result, Twitter card, and Open Graph share.

Fetch an image URL and convert it to a Base64 data URI for embedding directly in CSS or HTML.

Load a URL in headless Chromium, extract every computed CSS color, and list them as a sortable palette with swatches.