Network & API

Convert between bit and byte rates and work out the transfer time of a file.

Turn a curl command into Go, Python, JavaScript or PHP.

Resolve a hostname to its A and AAAA records.

Follow the Received chain hop by hop and check the authentication headers.

Build a header block from Name: value lines and check it against the chosen HTTP version.

Parse a raw header block into a table and flag duplicates and non-canonical names.

Expand or compress an IPv6 address and show its binary layout.

List the mail exchangers of a domain, lowest preference first.

Describe an IP address: family, scope, class, reverse name and reserved ranges.

List the authoritative name servers of a domain.

Search the well-known TCP and UDP ports by number, service or description.

Build a Postman v2.1 collection from a list of URLs.

Resolve an IP address back to its PTR name and show the containing block.

Inspect a remote certificate: validity dates, chain of trust, subject alternative names and days remaining.

Compute the network, mask and host range of an IPv4 or IPv6 CIDR block.

Fetch the TXT records of a domain and classify SPF, DKIM, DMARC and verification entries.

Split a URL into scheme, authority, path, query parameters and fragment.

Follow the redirects of a URL hop by hop and report each status, Location and timing.

Identify the browser, engine, operating system and device behind a User-Agent string.

Decode an RFC 6455 frame given as hex: opcode, mask, length and payload.

Query the registry of a domain or IP and extract the registrar, dates, status and name servers.