Look up any HTTP status code with its meaning, RFC reference and when to use it.
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Web & HTTP Tools
HTTP is simple until something goes wrong — a mysterious 4xx, a CORS error in the console, a redirect that loops, a header that never arrives. This category collects the tools that make the protocol visible: references for every status code and MIME type, parsers for headers, URLs, query strings and user agents, and live testers for CORS and redirects.
It also covers the developer workflow around APIs: turning a request into a cURL command (or a cURL command into code), and reading, formatting and validating OpenAPI and Swagger documents.
Tools in this category
Parse raw HTTP request/response headers into a structured table with explanations.
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Compose HTTP headers with presets for caching, CORS, security and content negotiation.
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Parse User-Agent strings into browser, version, engine, OS, device type and bot detection.
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Break a URL into protocol, host, port, path, query parameters, fragment and credentials.
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Parse and build query strings, including repeated keys and bracket-array notation.
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Test CORS configuration: send preflight and simple requests from a given origin and inspect the Access-Control-* headers.
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Trace redirect chains (301/302/307/308) and see every hop, status and final URL.
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Validate Content-Type headers and check that a response body actually matches its declared media type.
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Find the MIME type for a file extension, or the extensions for a MIME type.
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Validate and analyze IPv4 / IPv6 addresses and CIDR ranges: class, scope, private/public, binary and range size.
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Build request headers for REST APIs (auth, content negotiation, tracing) and export to cURL, fetch, axios or HTTP.
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Build correctly encoded query strings for API calls with pagination, filtering and sorting parameters.
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Compose JSON request bodies from a visual field editor and validate them before sending.
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Generate ready-to-run REST API request code in cURL, JavaScript fetch, axios, Python requests, Java, C#, Go and PHP.
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Build cURL commands from method, URL, headers, body and auth options.
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Parse a cURL command into method, URL, headers and body, then convert it to fetch, axios, Python or a structured request.
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Render an OpenAPI 3.x / Swagger 2.0 spec (JSON or YAML) as browsable endpoint documentation.
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Validate OpenAPI 3.x and Swagger 2.0 documents for structural errors and best-practice issues.
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Format OpenAPI specs, convert between JSON and YAML, and sort paths and schemas.
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Format and validate Swagger 2.0 JSON documents.
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Analyze a browser HAR file: failed and slow requests, redirects, large and repeated requests — and find the cookies and tokens it contains before you share it.
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