All tools
31 free tools for domains, email security, TLS, HTTP, networks and everyday developer work. Filter by category or search by name.
31 tools
Domain
- Domain HealthOne check for DNS, email authentication, TLS, security headers and redirects, with a grade per area and a full report.
- DNS LookupLook up DNS records by type, including reverse (PTR) lookups for IP addresses.
- WHOIS LookupSee who registered a domain, when it expires and which name servers it uses.
- Subdomain Takeover ScanFind subdomains whose DNS still points at a service that no longer serves them, before somebody else claims the name.
- DNS Migration CheckCompare what your current and your new nameservers answer, record by record, before you switch the delegation.
- Email SecurityCheck SPF, DKIM, DMARC, MTA-STS, TLS-RPT and BIMI for a domain and get the records to fix them.
- DMARC Report AnalyzerRead the DMARC aggregate reports your receivers send: who is sending as your domain, how much, and what passes.
- MX & SMTPCheck a domain's mail servers and test SMTP connections, STARTTLS and open relay.
- Blacklist CheckerCheck whether an IP address or a domain's mail server is listed on DNS blocklists.
- Email Header AnalyzerTrace delivery hops, read SPF, DKIM and DMARC results, and see whether they actually cover the From address.
- Record BuildersBuild SPF, DMARC, BIMI, MTA-STS and TLS-RPT records, meta tags and robots.txt with live checks as you type.
TLS
HTTP
- HTTP HeadersGrade a site's security headers and cookies, get the header lines to add, and build a Content-Security-Policy that the same check approves.
- Redirect CheckerTrace redirects from http and https, with and without www, to the final URL and spot loops and extra hops.
- SEO MetadataCheck a page's title, description, canonical, robots and Open Graph tags.
- Request InspectorParse a User-Agent string into browser, operating system, device and bot.
Network
- Ping & TraceroutePing a public host for loss and latency, or trace the route to it hop by hop.
- IP IntelligenceLook up an IP address's network, ASN, reverse DNS, registry allocation and abuse contact, or show your own.
- Port ScannerCheck which TCP ports on a public host accept connections, and read what each open port means on that host and what to do about it.
Developer
- JSON ToolsFormat, minify, repair and validate JSON with exact error positions, browse it as a tree, and convert between JSON, CSV and YAML.
- Code FormatterFormat and minify XML, HTML and CSS, and minify JavaScript, in your browser.
- Encoder / DecoderEncode and decode Base64, URLs and HTML entities, and convert number bases.
- URL & UTMSplit a URL into its parts and build campaign links with UTM parameters.
- Text UtilitiesCount words and characters, change case and turn titles into URL slugs.
- JWT DecoderDecode JWT header and claims, warn about the algorithm and header tricks that get tokens forged, sign new tokens, and verify HS, RS, PS and ES signatures in your browser.
- Regex TesterTest JavaScript regular expressions with highlighted matches, capture groups, a plain-English explanation, ready-made code and a catastrophic-backtracking check.
- Hash GeneratorHash text or a file with MD5, SHA-1, SHA-2, SHA-3 or HMAC.
- Password GeneratorGenerate strong random passwords in your browser with an entropy estimate.
- UUID GeneratorGenerate UUID v1, v3, v4, v5, v7 and ULID identifiers and decode existing UUIDs.
- Timestamp ConverterConvert Unix timestamps and dates across formats and time zones, and explain a cron expression.
- Color ConverterConvert HEX, RGB, HSL and OKLCH colours and check WCAG contrast.