Network Tools
URL parser, HTTP status codes, user-agent decoder, IPv4 CIDR calculator — everything you need to debug the wire.
7 tools in this category
DNS Lookup
Resolve any hostname to A, AAAA, MX, TXT, NS, CNAME, SOA, and CAA records — live, via Cloudflare DoH.
HTTP Status Codes
HTTP Status Code Reference — search every IANA code with retry guidance.
IPv4 CIDR Calculator
Subnet calculator — parse CIDR, split, supernet, and test containment in your browser.
Is My Website Alive?
Check if a site is up in under a second — TCP handshake, HTTP status, SSL expiry, response time. No install, no account.
What's My IP?
See your public IP address, user agent, and connection details — instantly, no tracking.
URL Parser
Break URLs into parts — scheme, host, port, path, query, fragment, IDN, and PSL.
User Agent Parser
Parse Browser User-Agent Strings — browser, OS, device, and bot detection.
Network debugging tools are traditionally CLI-heavy: `curl`, `dig`, `nmap`, `netcat`. But plenty of day-to-day work is string manipulation — parsing a messy URL from a log, decoding a User-Agent header, figuring out whether an IP falls inside a subnet. These tools are the browser-friendly versions.
URL parsing caveats
The WHATWG URL standard (what browsers implement) has subtle differences from RFC 3986. For example, http://example.com/../foo normalizes differently. Our URL Parser uses the WHATWG parser because that's what your JavaScript code will use, so results match at runtime. If you need strict RFC behavior, flag this in your test.
Subnets without math
The IPv4 CIDR tool gives you network, broadcast, first/last usable host, netmask, wildcard mask, and total address count for any /prefix. It also splits a CIDR into equal-size subnets and finds the supernet covering two addresses. RFC 3021 /31 point-to-point links are handled correctly (both addresses usable).
User-Agent sanity
The User-Agent string is a mess by design: every browser pretends to be Mozilla, Safari, Chrome, and sometimes all three. Our User-Agent tool extracts the actual browser name, OS, device type, and bot identification using the Client Hints–aware parsing rules. It handles modern quirks like reduced UA strings in Chrome.
Frequently asked questions
Does the URL Parser handle IDN (internationalized domains)?
Yes — it uses the browser's built-in URL constructor, which handles Punycode conversion automatically. `https://日本.jp` parses correctly.
Can the CIDR tool split into unequal subnets?
No — VLSM (variable-length subnet masking) is a longer workflow. The tool splits into equal-size subnets. For VLSM, split recursively (split /24 into two /25s, then split one /25 further).
Why doesn't my HTTP 418 appear in the reference?
It does, along with 449, 451, and all the standard codes. 418 (I'm a teapot) is there for completeness, even though RFC 2324 was an April Fools. Non-standard codes like Cloudflare's 52x and AWS's custom codes are annotated as vendor-specific.
Is the User-Agent parser up to date?
We update the parser when a new browser or major bot appears. If you hit a UA that misidentifies, open an issue with the raw string.