Free Online Network and Browser Tools
Diagnostics you would otherwise open a terminal or a reference tab for: subnet calculation, parsing a user agent string, looking up an HTTP status code or a MIME type, a WebSocket tester. Almost all of it is lookup and arithmetic running locally. The IP address lookup is the exception, and one of only two tools on the whole site that calls an external service, because your public address is by definition something only a server can tell you.
Tools in this category
- IP Address Lookup Validate and analyze an IPv4 or IPv6 address right in your browser — no network calls.
- IP Address Extractor Paste any text or logs and extract every IPv4 and IPv6 address, fully in your browser.
- Browser Information See your own browser, device, and environment details — user agent, OS, screen, timezone, and more, read locally in your browser.
- Screen Resolution Checker See your live screen resolution, available area, browser viewport size, pixel ratio, aspect ratio, orientation, and breakpoint — and watch them update instantly as you resize the window.
- Cookie Parser Parse a Cookie request header or a Set-Cookie response header into a clean, readable list of names, values, and attributes — right in your browser.
- HTTP Status Code Checker Look up any HTTP status code (200, 301, 404, 500…) to see its name, category, plain-English meaning, common causes, and how to fix it — plus a searchable reference of every standard code.
- MIME Type Checker Look up the MIME (media) type for a file extension and vice-versa. Type an extension like .png, svg, or .woff2 to get its MIME type, or search a MIME type to find the matching extensions — plus a searchable reference table of common text, image, audio, video, application, and font types.
- Query String Parser Paste a URL or a raw query string and parse every query parameter into a clean, readable key/value table — with URL-decoding, repeated-key grouping, and copy-as-JSON, all in your browser.
- Query String Builder Add key/value pairs and a base URL, and instantly build a correctly URL-encoded query string and full URL — with proper percent-encoding, empty-key skipping, and copy, all in your browser.
- Subnet Calculator Calculate IPv4 subnet details from an IP and CIDR prefix or subnet mask — network and broadcast address, usable host range, host count, wildcard mask, and more, entirely in your browser.
- IPv4 to Integer Converter Convert any IPv4 address into its 32-bit integer value — in decimal, hexadecimal, octal, and binary — instantly and entirely in your browser.
- Integer to IPv4 Converter Convert a 32-bit integer back into its dotted-decimal IPv4 address. Accepts decimal, hexadecimal, octal, and binary input and shows the IP plus its hex and binary forms, all in your browser.
- curl Command Generator Build a ready-to-run curl command from a simple form. Set the URL, HTTP method, headers, request body, basic auth, and common flags, and get a properly shell-escaped curl command you can copy and paste. Everything is generated in your browser.
- curl to fetch Converter Paste a curl command and instantly convert it into equivalent JavaScript fetch() code. The converter parses the URL, method, headers, request body, and basic auth, then prints clean, copyable fetch() code. It runs entirely in your browser and never sends the request.
- curl to axios Converter Paste a curl command and instantly convert it into equivalent JavaScript axios code. The converter parses the URL, method, headers, request body, and basic auth, then prints clean, copyable axios code using the request config or the axios.get/post shorthand. It runs entirely in your browser and never sends the request.
- fetch to curl Converter Paste a JavaScript fetch() call and instantly convert it into an equivalent curl command. The converter reads the URL, method, headers, and request body from your fetch() code, then prints a clean, copyable curl command with correct shell quoting. It runs entirely in your browser, parses the code as text, and never sends the request.
- WebSocket Tester Connect to any WebSocket server right from your browser. Enter a ws:// or wss:// URL, click Connect, and watch the live connection status as it goes from connecting to open. Send text messages and see a timestamped log of everything you send, every message the server sends back, and each connection event. Disconnect cleanly or clear the log anytime. It uses your browser's native WebSocket API and runs entirely client-side.