Web and Security Tools
Checks for people who run or look after websites. Trace a redirect chain, grade the security headers a site sends, see when an HTTPS certificate expires, look up DNS records after a change, find your public IP address, look up who registered a domain and when it expires, check SPF, DKIM and DMARC email records, test whether a website is up, validate an email address, review a page's meta tags and generate strong random passwords.
Results are shown as plain tables with clear pass and fail markers, so problems are easy to spot.
Passwords and encryption See all
Password GeneratorCreate strong random passwords of any length.Password Strength CheckerEstimate how long a password would take to guess, with pattern checks and suggestions.Text Encryption ToolLock a message with a passphrase using AES-256, and unlock it again later.TOTP Code Generator and TesterGenerate the six digit codes your two-step sign-in expects, and test a code against a secret key.Password Policy TesterTest a password against rules you choose, such as length, character types and well-known passwords.Random Key GeneratorGenerate random keys and secrets in hex, Base64 or letters and numbers for API keys, tokens and signing.Hash IdentifierPaste a hash to see which hash types it could be, judged from its length and format.PKCE Code Challenge GeneratorMake a PKCE code verifier and its S256 code challenge for OAuth sign-in, plus state and nonce values.SSH Key Fingerprint CalculatorPaste a public key to get its SHA-256 and MD5 fingerprints, type and size.
Headers and policies See all
Security Headers CheckerGrade a site's HTTP security headers from A to F.CSP Header BuilderBuild a Content-Security-Policy header by choosing where each kind of content may come from.CSP EvaluatorPaste a Content-Security-Policy and see which parts are weak, with a grade and plain explanations.SRI Hash GeneratorGet the integrity value for a script or style sheet and the tag that uses it.Permissions-Policy BuilderDecide which browser features your pages and embedded frames may use, and get the header.CORS Header Builder and ExplainerBuild the CORS headers for your API and check whether a request will need a preflight first.security.txt GeneratorWrite a security.txt file so researchers know how to report a problem on your site.Set-Cookie Header Builder and CheckerBuild a Set-Cookie header with the right flags, or paste one to check it for mistakes.Security Headers GeneratorChoose HSTS and other protective headers and get the exact lines to add, with warnings about risky settings.
Domains, DNS and SSL See all
Redirect CheckerTrace every redirect hop and status code for any URL.SSL Certificate CheckerCheck a site's HTTPS certificate, issuer and expiry date.DNS LookupLook up A, AAAA, MX, TXT, NS, CNAME, SOA and CAA records.What Is My IPSee your public IP address and reverse DNS instantly.WHOIS Domain LookupSee who registered a domain, when it expires and its name servers.Website Status CheckerFind out whether a website is up, how fast it answers and where it redirects.Domain Availability CheckerIncluded with UnlimitedSee which endings are taken for a name, and when the taken ones expire.IP Blacklist CheckerIncluded with UnlimitedCheck an IP address or domain against email and abuse blocklists.Subdomain FinderIncluded with UnlimitedFind a domain's subdomains and see which are live and where they point.IP & ASN LookupIncluded with UnlimitedSee which network owns an IP address, with its ASN, range and reverse DNS.SSL & Domain Expiry AlertsIncluded with UnlimitedSave your domains and get an email before the SSL certificate or the domain registration runs out.Certificate DecoderPaste a PEM certificate to see who it is for, who issued it, when it expires and which names it covers.CSR DecoderPaste a certificate signing request to check the names, key and signature before you send it to an authority.
Email and links See all
SPF, DKIM & DMARC CheckerCheck the email records that help your messages reach the inbox.Email Address ValidatorCheck an email address is written correctly and its domain accepts mail.Link UnshortenerIncluded with UnlimitedSee where a short or tracked link really goes before you click it.Email Header AnalyserPaste the raw headers of an email to see the route, the delays and the sender checks.Phishing Link InspectorCheck how a link is written for look-alike letters, hidden destinations and other tricks used in scams.DMARC Record GeneratorBuild a DMARC record for your domain with the right policy, report addresses and alignment.SPF Record Builder and CheckerBuild an SPF record or paste one to check it, with a count of DNS look-ups against the limit of 10.
Privacy and compliance See all
Cookie ScannerIncluded with UnlimitedList the cookies a page sets, with attributes, categories and weak settings flagged.UK GDPR 72 Hour Breach Deadline CalculatorWork out the deadline to tell the ICO about a personal data breach, with a countdown and a plan.URL Parameter StripperRemove tracking parts such as utm_ and fbclid from links before you share them.
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Guides to read first
SPF, DKIM and DMARC explained, step by step
A step-by-step guide to SPF, DKIM and DMARC email authentication, with example DNS records, a careful rollout order and fixes for the most common mistakes.
How to check when an SSL certificate expires
Find your SSL certificate expiry date, understand how long certificates last, avoid browser warnings and set alerts so renewal never catches you out.
How to check DNS records after moving hosting
Check A, AAAA, CNAME, MX, TXT and NS records after a hosting move, understand how long changes take to spread and avoid breaking your email in the process.