Free Tools

Domain, DNS & Security Tools

Free utilities for website owners, developers and system administrators. No account required. Tools FAQ

⚠ Critical PHP Vulnerability — CVE-2026-109618 & CVE-2026-109619 Two RCE flaws affect PHP 8.4 < 8.4.27, 8.3 < 8.3.36, 8.2 < 8.2.35. Check if your server is exposed. Check now →

Domain & DNS Tools

Run all tools in one place →
DNS Propagation Checker
See which global resolvers have picked up your DNS changes and how far propagation has spread.
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Email Security Checker
Analyse SPF, DMARC and DKIM. Counts SPF DNS lookups recursively against the 10-lookup RFC limit.
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Post Quantum TLS Check New
Test whether a domain supports post quantum hybrid key exchange (ML-KEM, NIST FIPS 203) and Encrypted Client Hello (ECH). Probes each ML-KEM group individually using OpenSSL 3.5.
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DNS Zone Recovery
Reconstruct a zone file from live DNS records including A, AAAA, MX, TXT and CNAME, ready to import.
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DNS Zone Transfer Test
Test whether nameservers allow AXFR zone transfer requests from unauthenticated clients.
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security.txt Checker
Validate a site's security.txt file for required fields, expiry and RFC 9116 compliance.
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Security Header Checker
Scan any site for HTTP security headers including CSP, HSTS and X-Frame-Options. Rescan after changes to see a plain-English diff of what changed and whether it was an improvement.
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WHOIS / RDAP Lookup
Registrar, creation and expiry dates, nameservers and DNSSEC status via RDAP with WHOIS fallback.
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SSL Certificate Checker New
Check certificate expiry date, days remaining, issuer, covered names and TLS version. Reads directly from the live handshake.
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PCI Tools

Tools for monitoring payment page security controls relevant to PCI DSS v4. PCI DSS SAQ A removed requirements 6.4.3 and 11.6.1 as individual requirements. These are PCI support tools, not universally mandatory for every SAQ A merchant.

Payment Processor Watcher
Daily SHA-256 hash monitoring of third-party payment processor scripts including Stripe, PayPal and Square. Free browser push notifications on change. Relevant to PCI DSS 6.4.3.
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SRI Checker
Find external scripts and stylesheets missing Subresource Integrity and generate sha256 / sha384 integrity hashes you can paste directly into your HTML. Relevant to PCI DSS 6.4.3.
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Payment Page Monitor
Check any checkout page for HTTPS enforcement, security headers, external scripts and mixed content. Generates an SHA-256 page fingerprint. Relevant to PCI DSS 11.6.1.
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Payment Script Inventory
Build a documented script inventory for any checkout page. Identifies known payment processors, checks SRI status and lets you record owner and business justification per resource. Relevant to PCI DSS 6.4.3.
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