Free Domain & Network Tools
Free online tools for domain research, DNS analysis, network diagnostics, and developer utilities.
Everything You Need for Domain Research & Network Diagnostics
Whose.Domains provides a comprehensive suite of free online tools built for anyone who works with domains, DNS infrastructure, or web servers. Whether you are a domain investor screening expired inventory, a developer debugging DNS propagation, a sysadmin auditing open ports, or an SEO professional running competitive research, our toolset covers every step of the workflow — no account or subscription required.
Start with a WHOIS Lookup to check ownership and expiry details for any domain, then dive deeper with the Domain Analyzer to review DNS records, SSL status, and IP geolocation in a single view. Use Bulk Domain Search to screen hundreds of candidate names at once, or the Domain History tool to trace past ownership changes and registration patterns. For live infrastructure checks, Ping Test, Port Checker, and SSL Certificate Checker give you instant visibility into server health and certificate validity.
All tools run directly in your browser and return results in seconds. Data is sourced from authoritative WHOIS servers, public DNS resolvers, regional Internet registries, and live socket connections — so results reflect the current state of the internet, not a cached snapshot.
Evaluate expiring domains, estimate market value with Domain Valuation, score trust signals via Domain Health Score, and monitor competitor portfolios.
Debug DNS configurations with DNS Analyzer, validate email deliverability with Email Checker, and format API payloads with JSON, XML, and HTML formatters.
Audit infrastructure with Reverse IP Lookup, test connectivity via Ping Test, verify firewall rules with Port Checker, and inspect TLS chains with SSL Checker.
Run Competitor Analysis, track domain authority trends, identify related domains with Related Domains, and uncover historical ownership patterns for due diligence.
What do you want to do?
Domain Tools
WHOIS Lookup
Free WHOIS lookup — instantly check domain owner, registrar, creation date, expiry, and nameservers for any domain worldwide.
RDAP Lookup
Query domain registration data via the modern RDAP protocol — structured JSON responses, better privacy handling than legacy WHOIS.
Domain Availability
Instantly check if a domain name is available to register across .com, .net, .org, and hundreds of other TLDs — no signup required.
Bulk Domain Search
Check availability and WHOIS status for hundreds of domains at once. Ideal for domain investors screening expiry lists or brand managers auditing portfolios.
Domain History
Trace past WHOIS snapshots, registrant changes, and ownership transfers for any domain. Essential due diligence before acquiring an expiring or aftermarket domain.
WHOIS Compare
Compare WHOIS records of two domains side by side — quickly spot differences in registrar, nameservers, registrant, or expiry dates.
Related Domains
Discover domains registered by the same owner or sharing nameservers and IP addresses — useful for competitive intelligence and brand monitoring.
Domain Health Score
Get a composite trust and health score for any domain, covering DNS configuration, SSL validity, domain age, and registration status — at a glance.
Domain Valuation
Estimate the market value of any domain name based on length, keyword demand, TLD, and comparable sales data. Free domain appraisal tool.
Domain Analyzer
Comprehensive domain research in one view: WHOIS, DNS records, SSL status, IP geolocation, estimated traffic, and SEO metrics — all aggregated instantly.
Competitor Analysis
Benchmark your domain against competitors — compare registration age, hosting infrastructure, SSL posture, and domain authority signals side by side.
DNS & Network Tools
DNS Analyzer
Inspect all DNS record types — A, AAAA, MX, CNAME, TXT, NS, SOA — to debug propagation issues, verify email routing, and audit DNS security configuration.
Reverse IP Lookup
Find all domains hosted on a given IP address or server. Useful for identifying shared hosting neighbors, investigating spam sources, or auditing hosting providers.
My IP Address
Instantly detect your current public IP address with full geolocation details — country, city, ISP, ASN, and timezone. No extensions or installs needed.
Ping Test
Test the reachability and response latency of any hostname or IP address. Quickly diagnose network downtime, packet loss, or slow server response times.
Port Checker
Verify whether TCP ports (80, 443, 22, 25, 3306, and more) are open or blocked on any host — essential for firewall audits and server accessibility checks.
SSL Certificate Checker
Inspect TLS/SSL certificate details including issuer, expiry date, SANs, and full chain validity. Catch certificate mismatches and near-expiry issues before they cause downtime.
Developer Tools
Email Checker
Validate email address syntax, check MX record configuration, detect disposable or temporary email providers, and verify deliverability before sending.
JSON Formatter
Beautify, validate, and minify JSON data online with syntax highlighting. Instantly spot malformed JSON and format API responses for readability.
XML Formatter
Format, validate, and minify XML documents with syntax highlighting and error detection. Supports large XML files including sitemaps and RSS feeds.
HTML Formatter
Beautify and format raw HTML code with proper indentation and live preview rendering. Clean up minified markup or templating output in one click.
Timezone Converter
Convert times between any two timezones worldwide — great for scheduling across distributed teams, API timestamp handling, and international deployments.
Frequently Asked Questions
Are all these tools completely free?
Yes — every tool on Whose.Domains is 100% free with no hidden charges. There are no premium tiers, no pay-per-lookup fees, and no usage caps. We cover server costs through non-intrusive advertising.
Do I need to create an account or sign up?
No account or registration is required. All tools run directly in your browser — just open the page and start using them immediately. We don't require an email address or any personal information to access any feature.
Where does the data come from?
Data is sourced from multiple authoritative systems: WHOIS queries go to official registry and registrar servers; DNS lookups use public resolvers (Google, Cloudflare, authoritative nameservers); IP geolocation uses MaxMind GeoIP2 and regional Internet registry (ARIN, RIPE, APNIC) data; SSL checks open live TLS connections to the target host. Results reflect the current state of the internet, not a cached snapshot.
How accurate and up-to-date are the results?
WHOIS and DNS results are fetched in real time on each query. WHOIS data accuracy depends on what registrars report — some registrants use privacy protection services, which replaces personal details with proxy contact information. DNS results reflect propagation as seen from our resolvers; changes may take up to 48 hours to propagate globally. IP geolocation accuracy is typically 95–99% at the country level and lower at city level.
Can I use these tools for commercial or professional purposes?
Yes. Our tools are widely used by domain investors, SEO agencies, IT consultants, security researchers, and developers for professional workflows. There are no restrictions on commercial use. If you need high-volume programmatic access, check our Developer API for rate limits and endpoints.
Is there an API available for bulk or automated lookups?
Yes. Whose.Domains provides a free REST API for WHOIS lookups, DNS queries, domain history, and more. See the API Documentation for available endpoints, request formats, and rate limit details. No API key is required for basic usage.
Why does WHOIS sometimes show privacy-protected contact details?
Many domain owners use WHOIS privacy protection (also called proxy or redaction services) offered by their registrar. This replaces the registrant's real name, address, and email with generic proxy contact information to reduce spam and protect personal data. This is standard practice and complies with ICANN policies. The domain's technical details (registrar, creation date, expiry, nameservers) are still visible.
What is the difference between WHOIS and RDAP?
WHOIS is the legacy protocol for querying domain registration data — it returns plain text responses and varies in format across registrars. RDAP (Registration Data Access Protocol) is its modern replacement: it returns structured JSON, supports internationalized domain names better, has standardized field names, and handles access control more gracefully. Both query the same underlying registration data; RDAP is simply cleaner and more reliable for programmatic use.
How do I check if a domain is about to expire?
Use our WHOIS Lookup to see the exact expiry date for any domain. For browsing domains expiring in bulk, visit the Expiring Domains list which shows thousands of domains expiring within the next 7–90 days, updated daily.
Do the tools work on mobile devices?
Yes. All tools are fully responsive and work on smartphones and tablets. The interface adapts to smaller screens — tables scroll horizontally, forms stack vertically, and results are readable without zooming. No app download is needed.