Network Tools
Look up DNS records, check IP addresses, query WHOIS data, and diagnose network issues. All tools run directly in your browser - fast, secure, and free.
Network
34 tools
DMARC Record Checker
Check DMARC records for any domain via Cloudflare DNS-over-HTTPS. Validate email authentication policy (none/quarantine/reject), analyse alignment settings (adkim, aspf), and extract reporting addresses (rua, ruf) - free online DMARC record checker.
DNS Leak Test
Check if DNS queries and WebRTC are leaking your real IP outside your VPN tunnel. Detects local IPs via WebRTC STUN requests, checks public IP and geolocation via free APIs, and identifies DNS resolvers - free online DNS leak test.
DNS Record Comparator
Compare DNS records across the Cloudflare, Google, DNS.SB, and AliDNS resolvers automatically. Detects differences in A, MX, NS, CNAME, TXT, AAAA, and SOA records with severity indicators - free online DNS comparison tool.
Reverse DNS Lookup
Look up PTR records for any IPv4 or IPv6 address via Cloudflare DNS-over-HTTPS. Instantly find the hostname behind any IP address with DNSSEC validation status and query time - free online reverse DNS lookup tool.
Cookie Security Checker
Paste any Set-Cookie header value and analyze its security configuration against best practices. Validates Secure flag, HttpOnly flag, SameSite policy (Strict/Lax/None), Expires/Max-Age validity, Path and Domain scope. Get a 0-100 security score per cookie with specific warnings and actionable recommendations - free.
Bulk DNS Lookup
Look up A records for up to 50 domains at once via Cloudflare DNS-over-HTTPS. Sortable results table with IP addresses, response times, TTL, DNSSEC validation status, error detection, and CSV export - free online bulk DNS lookup tool.
WebRTC Leak Test
Test if your real IP address is leaking through WebRTC while using a VPN or proxy. Detects local IP addresses via WebRTC ICE candidates from RTCPeerConnection and compares them against your public IP via ipify.org. IP classification (private, loopback, public) with pass/fail verdict, IP type badges, and remediation.
HTTP Header Checker
Fetch a URL from your browser and inspect the HTTP response headers it can read, with plain-English descriptions. Check status codes, security headers (HSTS, CSP, X-Frame-Options), caching rules, CORS policies, and content negotiation, with a curl command for headers a site hides - free online HTTP header checker.
HTTP Redirect Chain Checker
Check where a URL ends up after 301, 302, 307, and 308 redirects: whether it redirected, the final URL, status code and total time, from your browser (for sites allowing cross-origin requests), plus a curl command that lists every hop - free online HTTP Redirect Chain Checker.
Certificate Transparency Log Checker
Check if TLS certificates for any domain appear in Certificate Transparency logs via crt.sh. View issuer details, validity dates, SHA-256 fingerprints, Subject Alternative Names (SANs), and CT log names - free online CT log checker.
SPF Record Checker
Validate SPF records for any domain via DNS-over-HTTPS TXT lookup. Checks SPF syntax, DNS lookup limits (max 10), and common misconfigurations like missing -all policy, duplicate includes, and invalid IP addresses - free online SPF record checker.
HTTP Connectivity Test
Test if any URL is reachable and measure its fetch timing using the browser Performance API. Shows total load time, plus DNS resolution, TCP handshake, TLS handshake and TTFB when the server sends Timing-Allow-Origin, with an interactive waterfall chart - free online HTTP connectivity test.
HSTS Preload Checker
Check if a domain is in the HSTS preload list, using Firefox's copy of Chromium's list (the list Chrome, Edge, Safari and Firefox build in). Shows Preloaded or Not Preloaded status, includeSubDomains coverage and the matching preload entry with detailed explanations - free online HSTS preload checker.
IP to Binary/Hex Converter
Convert any IPv4 address to dotted-decimal, hexadecimal, packed hex, binary, packed binary (32-bit), decimal integer, and IPv6-mapped formats instantly. Smart input detection supports dotted-decimal, decimal integer, packed hex, and packed binary input with real-time conversion, IP class detection, and special.
Cache-Control Header Analyzer
Paste any Cache-Control header value and get a detailed analysis of every directive (max-age, public, private, no-cache, no-store, stale-while-revalidate, immutable, and more). Understand caching behavior, revalidation rules, and CDN implications with optimization recommendations - free online Cache-Control header.
cURL Command Generator
Build cURL commands visually with our interactive cURL command generator. Select HTTP method (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS), enter URL, add custom headers, set request body in JSON/form/raw format, configure authentication (Basic, Bearer, Digest), and toggle advanced options.
CORS Preflight Tester
Check from your browser whether a URL allows cross-origin requests with your custom headers, and get the exact CORS preflight (OPTIONS) as a curl command for any origin and method. Paste its output to analyze 6 Access-Control-* response headers with pass/fail checks and explanations.
CORS Header Validator
Paste CORS response headers and validate them against the CORS specification. Checks Access-Control-Allow-Origin, Allow-Methods, Allow-Headers, Allow-Credentials, Max-Age, Expose-Headers, and Vary with severity-based pass/fail analysis. Optionally verify against expected origin, method, and custom headers - free.
Vary Header Checker
Check the Vary HTTP header to understand caching behavior. Enter any Vary header value and see detailed analysis of how each header affects cache efficiency, with cache efficiency, performance, and security ratings. Detects Vary: *, missing Vary: Origin with CORS, User-Agent cache fragmentation, Cookie header issues.
Wildcard Mask Calculator
Convert subnet masks to wildcard masks (inverse masks) used in Cisco ACLs and routing protocols. Enter any dotted-decimal subnet mask or wildcard mask for instant bidirectional conversion with binary representation, CIDR notation, host counts, and subnet class analysis - free online Wildcard Mask Calculator.
X-Frame-Options Checker
Check if a website sets the X-Frame-Options header for clickjacking protection. Enter a URL for a live HEAD check (for sites that allow cross-origin requests and expose the header; otherwise get a curl command), or paste a value (DENY, SAMEORIGIN, ALLOW-FROM) for analysis and recommendations.
Bulk IP Lookup Tool
Look up geolocation for up to 20 IPv4 addresses at once via free public IP geolocation providers (ipwho.is, with freeipapi.com and ipinfo.io as fallbacks). Get country, city, ISP, coordinates, timezone, and AS number for each IP in a sortable table with CSV export - free online bulk IP lookup tool.
Referrer-Policy Checker
Check the Referrer-Policy header of a URL from your browser, or with a ready-made curl command when the site does not expose it. Detects the policy (strict-origin-when-cross-origin, no-referrer, etc.) and explains the referrer info sent for same-origin, cross-origin, and downgrade requests, with security ratings.
IP to CIDR Calculator
Given a start and end IPv4 address, find the most specific CIDR notation that covers the range. Converts any IP range to the minimal set of non-overlapping CIDR blocks with full subnet details: network address, subnet mask, wildcard mask, broadcast address, first/last usable IPs, and host counts - free online IP.
OAuth Scopes Reference
Browse and search OAuth 2.0 scopes across top providers: Google, Microsoft, GitHub, Slack, and Facebook. Filter by provider, search by scope name or description, and see detailed scope information including documentation links - free online OAuth scopes reference.
URL Parser
Parse any URL into its components: protocol, hostname, port, path, query parameters, and fragment. Shows both raw (encoded) and decoded values side by side with query parameter breakdowns, URL validation warnings, and copy-to-clipboard - free online URL parser.
Data URI Generator
Convert text and files to data URIs (data:[MIME-type];base64,...) instantly. Type or paste text, upload files, or drag and drop to convert. Auto-detects MIME types from over 60 file extensions and 10+ text content patterns (HTML, JSON, SVG, CSS, JavaScript, Markdown, YAML). Size analysis with overhead percentages.
Query String Builder
Build, encode, and decode URL query strings from key-value pairs. Add parameters in an interactive table with automatic URL-encoding, choose from Standard, Form URL-encoded, or Minimal encoding modes, load presets for UTM campaigns and API pagination, and copy the result with or without the leading ?
Domain Age Checker
Check the age of any domain in years, months, weeks, and days. Enter a domain name to get its creation date, registration timeline, registrar info, and SEO authority estimate based on domain age - all fetched from the official RDAP registry in real time. Free online domain age checker.
Open Redirect Checker
Test any URL for open redirect vulnerabilities. Scans query parameters for 40+ redirect parameter names, tries 14 bypass payloads via HEAD requests where cross-origin is allowed (redirecting payloads are flagged for curl verification), detects URL shorteners, with severity-based risk assessment.
DNS Lookup Tool
Free DNS lookup tool online. Look up A, AAAA, MX, CNAME, NS, TXT, SOA, CAA, PTR, and SRV records for any domain via DNS-over-HTTPS. Instant results - no signup required.
DNSSEC Checker
Free DNSSEC checker online. Check if any domain has DNSSEC enabled - query DS, DNSKEY, and RRSIG records via DNS-over-HTTPS. View cryptographic details, algorithm types, and key roles - no signup required.
Page Speed Checker
Free page speed checker online. Fetch Google PageSpeed Insights scores and Core Web Vitals for any URL. Check Performance, Accessibility, Best Practices, and SEO scores instantly - no signup required.
Ping Tool (Browser)
Free browser ping tool online. Measure HTTP response time to any public hostname via fetch timing. Get min, avg, max RTT, jitter, and packet loss - no signup required.