Validate and reshape a JSON string. mode=format pretty-prints, minify compacts, sort_keys recursively alphabetizes object keys. Returns a clear error for invalid JSON.

Run a JavaScript regular expression against a subject string and return each match with its index, positional capture groups, and any named groups. Flags are honored exactly: without the g flag only the first match is returned; with g, all matches.

Compute a cryptographic digest (hex) of UTF-8 text.

Generate one or more RFC-4122 version-4 UUIDs (1–100).

Encode or decode text as Base64, with an optional URL-safe alphabet.

Decode a JWT's header and payload and report whether a signature segment is present and whether the token is expired. Does NOT verify the signature — decoding only.