Ontwikkelaarstools

Calculate IPv4 subnet details from CIDR notation or a subnet mask. Get network, broadcast, and host ranges instantly.

Analyze CIDR blocks, convert prefix lengths to subnet masks, split networks, and check whether an IP belongs to a range.

Look up mail exchange (MX) DNS records for a domain, sorted by priority with mail host IP resolution.

Look up and validate SPF TXT records for a domain. Parse mechanisms, count DNS lookups, and review policy strength.

Scan common TCP ports on a public host — check which services are reachable from the server.

Trace the network path to a hostname or IP. Shows each hop, round-trip times, and whether the route completed.

Check if a website is online from the server. See HTTP status, response time, redirects, and key response headers.

Inspect HTTP response headers for any URL. Review security headers, caching directives, CORS, and server metadata.

Parse user agent strings to identify browser, engine, operating system, device type, and bot detection.

Compare two texts and highlight added, removed, and changed lines or words instantly in your browser.

Decode JSON Web Tokens to inspect the header, payload, and claims instantly in your browser — no data leaves your device.

Beautify and explore JSON with adjustable indentation, key sorting, a collapsible tree view, and structure stats.