The toolbox that
actually explains things
Free email authentication, DNS, network diagnostics, and web security tools. Clear results with real explanations – not just green and red dots.
Email Header Analyzer
Decode SPF, DKIM, DMARC, and routing hops from raw email headers.
Email Send Test
Send a real email to a test address and get instant authentication analysis – no header copying needed.
Deliverability Score
Full deliverability audit with a 0-100 score – SPF, DKIM, DMARC, blacklists, PTR, and prioritized fixes.
DNS Propagation Checker
Check how far a DNS record has propagated across 8 global resolvers. Essential after publishing any DNS change.
SMTP Diagnostic
Mail server health check – rDNS, blacklists, SPF, DMARC, MTA-STS, DANE/TLSA, with a score and fixes.
Routing Visualizer
Visual hop-by-hop diagram of the path an email took with per-hop delay timing.
Email Routing Map
Geographic world map showing where each server in the email path is located.
DNS Lookup
Query A, AAAA, MX, TXT, NS, CNAME, and CAA records via Cloudflare DNS.
MX Record Checker
Validate MX records, check priority ordering, confirm each mail server resolves.
MX Reputation Checker
Per-server reputation score – rDNS, blacklists, SPF, DMARC for each MX host.
SPF Record Checker
Validate SPF records, check lookup limits, decode mechanisms, find issues.
DMARC Record Checker
Validate DMARC records, decode every tag, check policy strength.
DKIM Record Checker
Look up DKIM public keys, validate key strength, auto-discover selectors.
DMARC Policy Tester
Simulate how a receiver evaluates DMARC – set SPF/DKIM results and see exactly what happens.
BIMI Lookup
Check BIMI records and brand indicator configuration for logo display in email.
SPF Record Builder
Build SPF records interactively with one-click presets and live lookup count.
DMARC Record Builder
Build a DMARC record step by step with plain-English guidance for every option.
WHOIS Lookup
Registration dates, expiry, registrar, and nameservers via RDAP.
PTR / Reverse DNS
Look up PTR records and verify forward-confirmed rDNS for any IP.
Blacklist Checker
Check an IP against 25 major DNSBLs simultaneously.
IP Geolocation
Country, region, ISP, ASN, and network type for any IP address.
Open Relay Tester
Check MX servers for open relay indicators and get manual SMTP test steps.
SSL/TLS Checker
Certificate expiry, SSL Labs grade, TLS versions, HSTS, and vulnerabilities.
HTTP Headers Inspector
Audit security headers, detect server leaks, inspect caching and CORS.
Subnet Calculator
IPv4 and IPv6 CIDR breakdown with host ranges, masks, and binary.