Network/HTTP

CORS Checker / Explainer

Explain step by step whether the browser will allow a cross-origin request — simple/preflight classification, Access-Control-* response header checks, and a verdict.

Credentials (fetch)

One per line, "Name" or "Name: value" — the value does not affect the classification.

Grab these from the Network tab in DevTools (the response itself or the OPTIONS preflight) or curl -I.

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Parse a URL query string into a JSON object, or build a query string back from JSON.

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Break a User-Agent string down into browser, engine, operating system, and device type.

Basic Auth Generator

Generate or decode an HTTP Basic Authentication header — Base64(username:password).

HTTP Headers Parser

Parse raw HTTP headers (from curl -I, DevTools, raw response) into a field list with descriptions and a security headers check.

Cookie Parser

Parse a Set-Cookie header or a Cookie/document.cookie string into name, value, attributes, and a check for common security mistakes.

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Generate a placeholder image of a given size for mockups and layout.

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Convert a number into text (in Ukrainian, Russian, or English), with an optional currency-amount mode for hryvnia, dollar, euro, or ruble.

JS Minify / Beautify

Compress JavaScript for production, or format minified code into a readable layout.

HTML Minify / Beautify

Compress HTML for production, or format minified markup into a readable layout.

Meta Tags / Open Graph Generator

Generate HTML meta tags for SEO, Open Graph (Facebook), and Twitter Card — with a live share-card preview.

robots.txt Validator

Check robots.txt — User-agent group structure, directives, and a path tester for allow/block decisions.