25 free IT utilities

Expand a CIDR block into its network, broadcast, mask, and usable host range.

Split a network into equal subnets, or size subnets to a required host count.

Convert an IPv4 address between dotted decimal, integer, hex, binary, and IPv6 forms.

Query A, AAAA, MX, TXT, NS, CNAME, SOA, SRV, and CAA records for a domain.

Registration and ownership details for a domain or IP address.

Check whether a TCP port is reachable and accepting connections from the internet.

Measure reachability and latency, and trace the path to a host.

Generate strong random passwords or passphrases with configurable rules.

Estimate entropy and time-to-crack, and spot the patterns that weaken a password.

Compute MD5, SHA-1, SHA-256, SHA-384, and SHA-512 digests of text.

Verify a downloaded file against a published SHA-256 or MD5 checksum.

Decode a JSON Web Token's header and claims, and check its expiry.

Inspect a site's certificate: issuer, validity dates, SANs, and chain.

Encode and decode Base64, including URL-safe variants.

Format, validate, minify, and convert between JSON and YAML.

Test a regular expression against sample text with live match highlighting.

Compare two blocks of text and highlight what changed, line by line.

Write Markdown and see the rendered output side by side.

Create a QR code for a URL, Wi-Fi network, contact card, or plain text.

Generate UUID v4 and v7 identifiers in bulk, plus ULIDs and nano IDs.

Random numbers, strings, hex, bytes, MAC addresses, and IP addresses.

Convert between Unix timestamps and human-readable dates across time zones.

Explain a cron expression in plain English and list its next run times.

Convert between HEX, RGB, HSL, and OKLCH, with contrast ratio checking.

Inspect response headers, redirect chains, and security header coverage.