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Free website & security tools

Paste a URL, get real results in seconds — an A+–F grade, the exact problems, and copy-paste fixes. No account, no credit card.
A+
Flagship · start here
Website Security Score
One URL in, one composite A+–F grade across headers, TLS, email and reputation — with the single most important fix surfaced first.
headers · TLS · email · reputation
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Security Header Checker
Grade your HTTP security headers A+–F and get copy-paste fixes for nginx, Apache, Caddy and PHP.
CSP · HSTS · X-Frame-Options
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SSL Certificate Checker
Check any certificate’s expiry countdown, chain, protocol, cipher and fingerprint.
TLS · expiry · chain
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DMARC, SPF & DKIM Checker
Look up your email-security records and stop attackers spoofing your domain.
SPF · DKIM · DMARC
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DNS Lookup
Resolve A, AAAA, MX, NS, TXT and CNAME records and check DNSSEC in one place.
A · MX · NS · TXT · DNSSEC
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DNS Propagation Checker
See how far your DNS change has spread — live answers from 21 resolvers worldwide on a map.
propagation · TTL · worldwide
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Website Uptime Test
Is your website down right now? Check status, latency and TTFB from our server.
status · latency · TTFB
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SLA & Downtime Calculator
Turn 99.9% into minutes of allowed downtime — or your actual downtime into an availability percentage.
99.9% · downtime · nines
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Cron Expression Explainer
Paste a cron expression, get plain English and the next 10 run times in your timezone.
cron · schedule · next runs
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IP Subnet Calculator
CIDR in, everything out: network, broadcast, usable range and host count for IPv4 and IPv6.
CIDR · IPv4 · IPv6
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CAA Record Generator
Build correct CAA records for your CAs and check what a domain currently allows to issue.
CAA · issue · issuewild
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Certificate Decoder
Paste a PEM certificate (or chain) and read its subject, SANs, validity, key and signature.
PEM · x509 · SANs
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SPF Record Checker
Parse your SPF record, walk every include and count DNS lookups against the 10-lookup limit.
SPF · includes · 10 lookups
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Redirect Chain Tracer
Follow every redirect hop — status, latency, TLS and cookies — and see what the chain costs you.
301 · 302 · hops · latency
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Email Blacklist Checker
Check an IP or domain against a dozen DNSBLs at once, with delisting links for anything found.
DNSBL · Spamhaus · delisting
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TLS Protocol Scanner
See which TLS versions a server accepts — 1.0 through 1.3 — with the negotiated cipher and a grade.
TLS 1.3 · ciphers · grade
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Email Header Analyzer
Paste raw email headers and get the hop-by-hop delivery timeline, delays and SPF/DKIM/DMARC verdicts.
Received · delays · spoofing
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These are the real checks — not a demo

Every tool here runs the exact same engine CompleteStatus uses for continuous monitoring. Try them free as one-off checks — then let CompleteStatus run them 24/7, confirm issues with a second probe, and alert you the moment anything changes.
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Frequently asked questions

Yes — every tool here is completely free, needs no signup and only scans public websites. They run the same engine CompleteStatus uses to monitor sites continuously.

No account is required. Paste a URL or domain and get real results instantly. Create a free CompleteStatus account only if you want continuous monitoring and alerts.
Uptime is table stakes. We watch the rest — security headers, email authentication, certs and DNS, with the fix attached.
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