Network & API

DNS, IP, ports and HTTP utilities.

54 tools

ALPN Protocol ID Reference All registered ALPN protocol identifiers — h2, h3, http/1.1 and more.
API Rate Limit Calculator Convert request quotas into per-second, per-minute and spacing guidance.
Authorization Header Parser Decode a Basic/Bearer/Digest Authorization header.
BGP / ASN Reference Look up well-known autonomous system numbers — Google, Cloudflare, ISPs…
CAA Record Validator Validate CAA DNS record syntax (flag, tag, value).
Cache-Control Builder Compose the HTTP Cache-Control header from directives.
CIDR / Subnet Calculator Break a CIDR block into network, mask, broadcast, first/last and host count.
CORS Preflight Simulator Simulate a browser CORS preflight without making any network requests.
curl → Code Converter Convert a curl command into JS fetch, PowerShell or .NET HttpClient code.
DKIM Key Generator Generate an RSA key pair and the matching DKIM DNS TXT record.
DMARC Record Builder Build a DMARC TXT record with policy, alignment and reporting tags.
DMARC RUA Parser Parse a DMARC aggregate (RUA) XML report into a readable summary.
DNS Lookup Resolve A, AAAA, MX, TXT, NS, CNAME and SOA records via DNS-over-HTTPS.
Domain Portfolio Manual record of owned domains: registrar, renewal price, expiry, auto-renew, nameservers, notes.
Email Header Analyzer Parse email headers and Received hops.
Email Header Analyzer Pro Trace the Received hops, SPF/DKIM/DMARC results and DKIM signature of any email.
Email Syntax Validator Validate email address syntax without contacting mail servers.
HTTP Header Inspector Fetch any URL and review its response headers + security headers.
HTTP Range Header Builder Build a 'Range: bytes=…' header for HTTP byte-range requests.
HTTP Request Tester Send any HTTP request and inspect the full response.
HTTP/3 & QUIC Reference Core concepts behind HTTP/3 and QUIC, one short paragraph each.
IP Address Inspector Classify any IPv4 / IPv6 address: public, private, loopback, link-local, multicast.
IPv4 ↔ Integer Convert IPv4 between dotted, integer, hex and binary.
IPv6 Expand / Compress Expand and compress IPv6 addresses; detect ULA.
IPv6 ULA Prefix Generator Generate a random /48 IPv6 unique-local prefix (RFC 4193).
JSON-RPC 2.0 Builder Compose JSON-RPC 2.0 requests, notifications and responses.
MAC / OUI Vendor Lookup Identify the manufacturer for a MAC address's first 3 bytes.
MAC Address Tools Parse, classify and re-format a MAC / EUI-48 address.
mDNS / Bonjour Service Type Reference Common mDNS / DNS-SD service type names with brief descriptions.
MTU & Bandwidth Calculator Compute MTU overhead, fragmentation and transfer time at various bandwidths.
OAuth URL Builder Build OAuth 2 authorization URLs.
OG / Twitter Card Multi-Platform Previewer Preview how a page's OpenGraph / Twitter Card tags render on Facebook, Twitter, LinkedIn, Slack, Discord and iMessage.
QUIC Frame Reference Common QUIC frame types with their hex codes and purpose.
Random IP / MAC Generator Generate random IPv4, IPv6 ULA or MAC addresses for mocking.
RFC Highlights Reference Most-cited Internet RFCs by number with a one-line title.
robots.txt + sitemap.xml Cross-Validator Validate robots.txt and sitemap.xml together — including cross-checks (sitemap URL blocked by robots).
Saved API Requests Persist HTTP request templates (method, URL, headers, body).
Set-Cookie Parser Parse a Set-Cookie header into structured fields.
SMTP / FTP / IMAP Codes Searchable reference of SMTP, FTP and IMAP response codes.
SNMP OID Reference Common SNMP OIDs for system uptime, interfaces, CPU and memory.
SPF Record Builder Build an SPF TXT record from common include / ip4 / ip6 / mx mechanisms.
SRV Record Builder Build a DNS SRV record from service, proto, name, priority, weight, port and target.
SSL Cert Expiry Tracker Saved hostnames probed over TLS to read leaf cert subject, issuer, validity window and SAN list.
Subnet Aggregator Collapse a list of IPv4 CIDRs into the smallest covering set.
Subnet Divider Split a CIDR block into 2ⁿ equal subnets.
TCP Port Checker Test whether a TCP port is reachable from our server.
TLS Cipher Suites Reference of common TLS 1.2 / 1.3 cipher suites with strength notes.
TLS Handshake Reference Searchable reference for the TLS 1.2 / 1.3 handshake steps.
Uptime Watchlist Saved list of URLs with manual on-demand HEAD/GET probes and a rolling check history.
User Agent Parser Decode a User-Agent string into browser, engine, OS and device.
Webhook HMAC Sign / Verify Compute HMAC signatures for webhook bodies (Stripe, GitHub…).
WebSocket Echo Tester Connect to any public ws:// or wss:// endpoint, send text/binary frames, watch the response.
WebSocket Tester Open a WebSocket, send one message and show the first response.
Whois / RDAP Lookup Look up domain registration data via RDAP-over-HTTPS.