Skip to main content Module string Copy item path Source fieldmask_covers True when path is equal to candidate or is a sub-path of it
(i.e. candidate is a prefix at a path-segment boundary). is_address address = hostname OR IP. is_email Email — permissive RFC 5321 addr-spec. protovalidate’s reference
implementation allows leading/trailing and consecutive dots in the
local part but rejects a trailing dot on the domain. is_header_name Well-known regex — HTTP header name. is_header_value Well-known regex — HTTP header value. strict=true delegates to
http::HeaderValue::from_bytesstrict=false
is looser (no CR/LF/NUL). is_host_and_port Hostname plus :port (0..=65535). is_hostname RFC 1035 hostname — labels of 1..=63 LDH characters, total ≤253 chars,
and the final label must not be all digits. is_ip IPv4 OR IPv6. is_ip_prefix IPv4 or IPv6 canonical prefix. is_ip_with_prefixlen Either IPv4 or IPv6 with a prefix length. is_ipv4 IPv4 in dotted-quad form. is_ipv6 IPv6 — any valid RFC 4291 textual form. Also accepts RFC 6874 zone-id
suffix %<zone> (any non-null characters). is_ipv4_prefix IPv4 canonical prefix — prefix length /N AND host bits zero. is_ipv4_with_prefixlen IPv4 with prefix length /N (0..=32). is_ipv6_prefix IPv6 canonical prefix — prefix length AND host bits zero. is_ipv6_with_prefixlen IPv6 with prefix length /N (0..=128). is_protobuf_dot_fqn Like is_protobuf_fqn but rejects leading/trailing dots and double dots. is_protobuf_fqn Protobuf FQN: dot-separated identifiers (no leading digit per segment). is_tuuid Trimmed UUID — same bytes without dashes (32 hex characters). is_ulid Canonical 26-char Crockford ULID. is_uri URI per RFC 3986 §3. Accepts absolute URIs (scheme required). is_uri_ref URI reference per RFC 3986 §4.1. Either a URI or a relative-ref. is_uuid Canonical hyphenated UUID per RFC 4122 §3 — 36-char 8-4-4-4-12 hex form.