Best Network & IP Tools
A hand-checked list of the best free network & ip tools for developers. Every tool runs in your browser — no upload, no login, no API key.
31 tools
Subnet Calculator
Network & IP
Calculate network, broadcast, host range, and mask from an IPv4 CIDR.
CIDR Range Expander
Network & IP
Expand a CIDR block into individual addresses, or compress a range into CIDR blocks.
IP Converter
Network & IP
Convert IPv4 to decimal/hex/binary, and expand or compress IPv6.
URL Parser
Network & IP
Break a URL into protocol, host, port, path, query, and hash.
Query String Converter
Network & IP
Convert between URL query strings and JSON, with nested bracket support.
User Agent Parser
Network & IP
Parse a user-agent string into browser, engine, OS, and device type.
HTTP Status Codes
Network & IP
Searchable reference of HTTP status codes with meaning and usage guidance.
MAC Address Tools
Network & IP
Validate and reformat MAC addresses, and look up the OUI vendor prefix.
Port Number Lookup
Network & IP
Search well-known TCP/UDP ports and their services.
HTTP Headers Explainer
Network & IP
Look up common HTTP headers and explain pasted raw headers.
DNS Record Types Reference
Network & IP
Searchable reference of DNS record types with examples.
IPv6 Expander/Compressor
Network & IP
Expand an IPv6 address to full form or compress it to shorthand.
MIME Type Lookup
Network & IP
Search file extensions and their MIME types.
HTTP Cache Header Planner
Network & IP
Plan Cache-Control, ETag and max-age headers for any asset type.
IP & CIDR List Validator
Network & IP
Validate and normalise lists of IPv4, IPv6 and CIDR entries offline.
OAuth URL Builder
Network & IP
Build OAuth 2.0 / OIDC authorization URLs with PKCE support.
Cookie Attribute Analyzer
Network & IP
Parse Set-Cookie headers and flag security issues.
HTTP Header Comparator
Network & IP
Diff two sets of HTTP headers, case-insensitively.
DNS Lookup
Network & IP
Query A, AAAA, MX, TXT, NS, CNAME and other DNS records for any domain.
Punycode / IDN Converter
Network & IP
Convert internationalised domain names to punycode and back.
URL Redirect Chain Analyzer
Network & IP
Trace every redirect hop with status codes, timing and the final URL.
Bulk URL Status Checker
Network & IP
Check HTTP status codes and redirects for many URLs at once.
Bulk File Downloader
Network & IP
Paste many URLs and save every file one by one, with a pause between downloads.
IP Geolocation & Reverse IP Lookup
Network & IP
Find the city, country, ISP and ASN behind any IP address or domain.
What Is My IP
Network & IP
Instantly see your public IPv4/IPv6 address, location, ISP and browser details.
Internet Speed Test
Network & IP
Measure download, upload, latency and jitter from your browser.
WHOIS Lookup
Network & IP
Look up domain and IP registration data over RDAP, the modern WHOIS.
SPF / DKIM / DMARC Generator & Checker
Network & IP
Check and build the three DNS records that stop your domain being spoofed.
MX & Mail Server Checker
Network & IP
See which servers accept a domain's mail and whether its policies are set.
Blacklist (RBL) Checker
Network & IP
Check an IP or domain against the major email blacklists at once.
HTTP/2 & TLS Version Test
Network & IP
See which TLS versions a site accepts and whether it serves HTTP/2.