SPF, DKIM, DMARC, DNS, SSL checker, CSR decoder, certificate bundle builder and more — all from your browser, free forever.
Check if your domain has a valid Sender Policy Framework record and analyze its configuration.
💡 What is SPF? SPF is a DNS TXT record that lists IPs authorized to send email for your domain. Format: v=spf1 include:... -all
Verify your DKIM public key record by entering the selector and domain.
💡 The DKIM record lives at selector._domainkey.yourdomain.com. Common selectors: default, google, mail, s1, s2
Check your domain's DMARC policy — reject, quarantine, or monitor.
Query any DNS record type — A, AAAA, CNAME, TXT, NS, MX, SOA, CAA and more.
Find the mail servers responsible for accepting email for a domain.
Look up domain registration details, nameservers, and expiry dates via RDAP protocol.
Measure HTTP response latency to any host. Tests reachability and measures round-trip time.
Test if a specific TCP port is open on a given host. Useful for firewall and service diagnostics.
Trace the network path and hops to a target host.
Find your public IP address along with geographic location, ISP, and connection details.
Check SSL/TLS certificate validity, expiry, issuer chain, and configuration for any domain.
💡 Note: Browser security restricts direct TCP/TLS access. This tool uses public SSL APIs to fetch certificate details. For private/internal hosts, use openssl s_client -connect host:443 | openssl x509 -noout -text
Decode and inspect a Certificate Signing Request (CSR). Paste your PEM-encoded CSR below to view the Subject, SANs, key size, and signature algorithm.
💡 Generate CSR on Linux: openssl req -new -newkey rsa:2048 -nodes -keyout private.key -out request.csr
Decode any X.509 SSL certificate. View subject, issuer, validity period, SANs, key usage, and fingerprints.
💡 View cert from Linux: openssl x509 -in certificate.crt -text -noout
Combine your certificate, intermediate CA, and root CA into a properly ordered certificate bundle (.pem / .crt chain).
💡 Correct bundle order: Server Cert → Intermediate → Root CA. Nginx uses this in ssl_certificate. Apache uses SSLCertificateChainFile for intermediate only.
Combine your certificate, private key, and CA chain into a .pfx or .p12 file for use with IIS, Windows, Java keystores, and load balancers.
🖥️ Generate PFX via OpenSSL (recommended for production):
openssl pkcs12 -export \
-out certificate.pfx \
-inkey private.key \
-in certificate.crt \
-certfile ca-bundle.crt \
-name "example.com"