Network & API Tools
Network and API debugging helpers: build HTTP requests, look up DNS and WHOIS records, check SSL certificates, parse user agents and convert cURL commands to code.
13 free tools — no ads, no sign-up, everything runs in your browser.
Bandwidth Calculator
Estimate how long a file takes to transfer at a given connection speed — correctly handling bits vs bytes (Mbps vs MB/s) and SI vs binary size units
DNS Lookup Tool
Query DNS records and resolve domain names to IP addresses
Email Header Analyzer
Parse email message headers to trace routing and authentication
HTTP Header Builder
Assemble HTTP request headers from a form and export them as a raw request block, a curl command, or a JavaScript fetch() call
HTTP Header Parser
Paste raw HTTP request or response headers and get a clean, structured breakdown with explanations for common headers like Cache-Control, CORS and security headers.
HTTP Request Builder
Test APIs and HTTP endpoints with customizable requests
IP Address Lookup
Comprehensive IP geolocation lookup with detailed analysis, bulk processing, history tracking, and security insights
IPv6 Address Expander
Expand a compressed IPv6 address to its full 8-group form and compress it back per RFC 5952 — with validation, embedded-IPv4 support, and a per-group breakdown
SSL Certificate Checker
Analyze SSL/TLS certificates for any domain, check expiration dates, certificate chains, and security details
Subnet Calculator
Calculate IPv4 and IPv6 subnets from CIDR notation — network address, broadcast, usable host range, subnet mask, wildcard mask, and a visual bit map
URL Parser
Break a URL into its components and decode query parameters
User Agent Parser
Parse User-Agent strings to identify browser, OS and device.
WHOIS Lookup
Lookup domain registration information including registrar, creation date, expiration date, and name servers.