title: Supported Key Types
role: manual
tags: #manual #meta #reference #zettel #zettelstore
syntax: zmk
back: 00001005090000 00001006000000 00001007705000 00001012053800 00001012931200
backward: 00001005090000 00001006000000 00001006020000 00001007705000 00001012053800 00001012931200
box-number: 1
copyright: (c) 2020-present by Detlef Stern <ds@zettelstore.de>
created: 20210126175322
forward: 00001006020000 00001006031000 00001006031500 00001006032000 00001006032500 00001006033000 00001006033500 00001006034000 00001006034500 00001006035000 00001006035500 00001007706000
lang: en
license: EUPL-1.2-or-later
modified: 20250708154024
published: 20250708154024
visibility: public

All [supported metadata keys](00001006020000) conform to a type.

User-defined metadata keys conform also to a type, based on the suffix of the key.



The name of the metadata key is bound to the key type

Every key type has an associated validation rule to check values of the given type.
There is also a rule how values are matched, e.g. against a [search value](00001007706000) when selecting some zettel.
And there is a rule how values compare for sorting.

* [Credential](00001006031000)
* [EString](00001006031500)
* [Identifier](00001006032000)
* [IdentifierSet](00001006032500)
* [Number](00001006033000)
* [String](00001006033500)
* [TagSet](00001006034000)
* [Timestamp](00001006034500)
* [URL](00001006035000)
* [Word](00001006035500)