NetworkAI
  • MonitoringCertificate & Domain MonitorDaily checks of TLS certificates, domain registration and DNS, with alerts when a renewal fails.
  • AssessmentSecurity AssessmentA passive security report for a domain you own: TLS, DNS, email authentication, headers and registration.
Free tools
Start hereDomain Health CheckSSL, DNS, email authentication, security headers and expiry in one scored report.Run a health check →
Domain
  • Bulk Domain Expiry Checker
  • RDAP Domain Lookup
  • WHOIS Lookup
SSL / TLS
  • SSL Certificate Checker
  • Bulk SSL Expiry Checker
  • 47-Day Certificate Lifetime Calculator
  • Certificate Lifetime Readiness
  • Post-Quantum TLS Checker
DNS
  • DNS Lookup
  • MX Lookup
  • CAA Record Checker
  • DNS Propagation Checker
  • TXT Record Lookup
  • NS Lookup
  • CNAME Lookup
  • Reverse DNS Lookup
Email authentication
  • SPF Record Checker
  • SPF Record Generator
  • DMARC Record Checker
  • DMARC Record Generator
  • DKIM Record Checker
  • Email Sender Requirements Checker
Website security
  • Security Headers Checker
Network & IP
  • What Is My IP Address
  • Subnet Calculator
All free tools →
PricingDocsGuides
Log inStart free
  • MonitoringCertificate & Domain MonitorDaily checks of TLS certificates, domain registration and DNS, with alerts when a renewal fails.
  • AssessmentSecurity AssessmentA passive security report for a domain you own: TLS, DNS, email authentication, headers and registration.
Free tools
Start hereDomain Health Check
Domain
  • Bulk Domain Expiry Checker
  • RDAP Domain Lookup
  • WHOIS Lookup
SSL / TLS
  • SSL Certificate Checker
  • Bulk SSL Expiry Checker
  • 47-Day Certificate Lifetime Calculator
  • Certificate Lifetime Readiness
  • Post-Quantum TLS Checker
DNS
  • DNS Lookup
  • MX Lookup
  • CAA Record Checker
  • DNS Propagation Checker
  • TXT Record Lookup
  • NS Lookup
  • CNAME Lookup
  • Reverse DNS Lookup
Email authentication
  • SPF Record Checker
  • SPF Record Generator
  • DMARC Record Checker
  • DMARC Record Generator
  • DKIM Record Checker
  • Email Sender Requirements Checker
Website security
  • Security Headers Checker
Network & IP
  • What Is My IP Address
  • Subnet Calculator
All free tools →
PricingDocsGuides
Start freeLog in
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  2. /Free tools

Free domain, certificate and email tools

Fast, ad-free checks for the things that quietly break a domain: certificates, DNS, email authentication, security headers and registration. No signup — and when you want the important ones run every day, that is one click away.

Start here

Domain Health Check

SSL, DNS, email authentication, security headers and expiry in one scored report.

Run a health check

Domain

All Domain tools →

Check a domain's overall health and when its registration expires, straight from registry data.

Domain reports

  • Domain Health Check

    SSL, DNS, email authentication, security headers and expiry in one scored report.

Registration & WHOIS

  • Bulk · up to 20

    Bulk Domain Expiry Checker

    Registration expiry dates for up to 20 domains from RDAP registry data.

  • RDAP Domain Lookup

    Registration and expiry dates, registrar, status and nameservers from the registry.

  • WHOIS Lookup

    Registrar, creation and expiry dates, domain age, status codes and name servers for any domain.

SSL / TLS

All SSL / TLS tools →

Check certificates: expiry, chain, hostname match and readiness for 47-day lifetimes.

Certificate checks

  • SSL Certificate Checker

    Expiry, chain completeness, hostname match, revocation status and key strength.

  • Bulk · up to 20

    Bulk SSL Expiry Checker

    Certificate expiry dates for up to 20 hosts at once, most urgent first.

Lifetime & renewal

  • Runs in your browser

    47-Day Certificate Lifetime Calculator

    Maximum lifetime, renewal date and renewals per year for any issue date.

  • Certificate Lifetime Readiness

    How a live certificate compares with the 200-, 100- and 47-day limits.

TLS configuration

  • Post-Quantum TLS Checker

    Does a server negotiate the hybrid X25519MLKEM768 key exchange? Tested with a real handshake.

DNS

All DNS tools →

Look up any DNS record, check propagation across public resolvers, and see which certificate authorities a domain allows.

Record lookups

  • DNS Lookup

    A, AAAA, CNAME, MX, NS, TXT, CAA and SOA records in one view.

  • MX Lookup

    Mail servers in priority order, what they resolve to, and the provider behind them.

  • TXT Record Lookup

    Every TXT record on a domain, with SPF, DMARC and verification tokens labelled.

  • NS Lookup

    A domain's name servers, their IP addresses, and whether each one answers with the same zone.

  • CNAME Lookup

    Follow a CNAME chain hop by hop to the final hostname and its IP addresses.

  • Reverse DNS Lookup

    The PTR hostname for an IPv4 or IPv6 address, and whether it resolves back to the same IP.

Propagation

  • DNS Propagation Checker

    See whether 20 public DNS resolvers return your new A, MX, TXT or CNAME record yet.

Security records

  • CAA Record Checker

    Which certificate authorities may issue for a domain, including inherited rules.

Email authentication

All Email authentication tools →

Check and build the SPF, DKIM and DMARC records that stop your domain being spoofed.

Authentication checks

  • SPF Record Checker

    The full include tree and the DNS-lookup count against the limit of 10.

  • DMARC Record Checker

    Policy, alignment, report addresses and the mistakes that stop reports arriving.

  • DKIM Record Checker

    Find DKIM keys by selector and check their type and size.

Deliverability

  • Email Sender Requirements Checker

    One verdict for the Gmail, Yahoo and Outlook bulk-sender rules: SPF, DKIM, DMARC and the rest.

Record generators

  • Runs in your browser

    SPF Record Generator

    Build a valid SPF record from your providers and server IPs. Runs in your browser.

  • Runs in your browser

    DMARC Record Generator

    Create a DMARC record with the right policy and reporting. Runs in your browser.

Website security

All Website security tools →

Grade a site's HTTP security headers and get the configuration to fix them.

  • Security Headers Checker

    An A–F grade for HTTP security headers, with copy-paste server config.

Network & IP

All Network & IP tools →

Find your public IP address and work out subnets, host ranges and masks for IPv4 and IPv6.

Your IP address

  • What Is My IP Address

    Your public IPv4 address, reverse DNS name, network (ASN) and country, with a copy button.

IP & subnet calculators

  • Runs in your browser

    Subnet Calculator

    IPv4 and IPv6 CIDR calculator: network, broadcast, host range, mask and subnet splits. Runs in your browser.

Run the important checks every day

These tools show you today. NetworkAI's monitor checks certificates and registrations daily and alerts you when a renewal has not happened — by email, Slack or webhook.

See the monitor
NetworkAI

Renewal-failure alerts for TLS certificates and domain registrations.

Product

  • Certificate monitor
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  • Start free

Free tools

  • Domain Health Check
  • SSL Certificate Checker
  • SPF Record Checker
  • DMARC Record Checker
  • Security Headers Checker
  • DNS Lookup
  • All free tools →

Tool categories

  • Domain
  • SSL / TLS
  • DNS
  • Email authentication
  • Website security
  • Network & IP

Resources

  • Documentation
  • Slack & webhook alerts
  • Guides
  • All comparisons
  • NetworkAI vs UptimeRobot
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