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.
32 free tools — no ads, no sign-up, everything runs in your browser.
API Mock Server
Define mock REST routes and intercept fetch calls client-side
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
Broken Link Checker
Extract http(s) links from pasted HTML and check them via proxy
cURL to Code Converter
Convert cURL commands to code snippets in multiple languages. Parse cURL and generate JavaScript, Python, PHP, and more.
DNS Lookup Tool
Query DNS records and resolve domain names to IP addresses
DNS Propagation Checker
Compare DNS answers from global public resolvers and see propagation consensus instantly
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
IP Intelligence
PTR, ASN, and Spamhaus RBL intelligence for public IP addresses
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
MX Record Lookup
Inspect MX (Mail Exchanger) records, priority preferences, and email provider detection
Network Info
Browser connection details and optional public IP via proxy
NS Record Lookup
Inspect Name Server (NS) DNS records and authoritative DNS provider configurations
Open Graph Debugger
Inspect og: meta tags from pasted HTML to debug link previews on Facebook, LinkedIn and more
Port Reference
Search common TCP and UDP ports with service names, protocols, categories, and IANA status
Port Scanner Guide
Educational guide to port scanning — no actual scanning performed
Postman Collection Builder
Build Postman Collection v2.1 JSON from a visual request form
Reverse DNS (PTR) Lookup
Perform reverse DNS lookups for IPv4 and IPv6 addresses using DNS-over-HTTPS
SSL Certificate Checker
Analyze SSL/TLS certificates for any domain, check expiration dates, certificate chains, and security details
SSL/TLS Deep Inspector
Grade TLS configuration with chain trust, protocol, key strength, and expiry checks
Subdomain Explorer
Discover subdomains from Certificate Transparency logs without brute force
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
TXT Record & SPF/DKIM Checker
Query TXT records and analyze SPF, DKIM, and DMARC email authentication security policies
URL Parser
Break a URL into its components and decode query parameters
URL Redirect Chain Checker
Trace HTTP redirect hops — status codes, Location headers, and final URL
User Agent Parser
Parse User-Agent strings to identify browser, OS and device.
Webhook Tester
Send POST webhooks to localhost directly or remote URLs via the DevTools proxy
WebSocket Frame Parser
Decode RFC 6455 WebSocket frames from hex — opcode, mask, payload
WHOIS Lookup
Lookup domain registration information including registrar, creation date, expiration date, and name servers.