title: Reserved zettel identifier
role: manual
tags: #design #manual #zettelstore
syntax: zmk
backward: 00001006050000
box-number: 1
copyright: (c) 2020-present by Detlef Stern <ds@zettelstore.de>
created: 20210721105704
forward: 00001000000000 00001004020000 00001005090000 00001006050000 00009999999998
lang: en
license: EUPL-1.2-or-later
modified: 20240708154858
published: 20240708154858
visibility: public

[[Zettel identifier|00001006050000]] are typically created by examine the current date and time.
By renaming[^The rename operation id deprecated and will be removed in version 0.19 or later.] a zettel, you are able to provide any sequence of 14 digits[^Zettel identifier format will be migrated to a new format after version 0.19.].
If no other zettel has the same identifier, you are allowed to rename a zettel.

To make things easier, you must not use zettel identifier that begin with four zeroes (''0000'').

All zettel provided by an empty zettelstore begin with six zeroes[^Exception: the predefined home zettel ''00010000000000''. But you can [[configure|00001004020000#home-zettel]] another zettel with another identifier as the new home zettel.].
Zettel identifier of this manual have be chosen to begin with ''000010''.

However, some external applications may need at least one defined zettel identifier to work properly.
Zettel [[Zettelstore Application Directory|00009999999998]] (''00009999999998'') can be used to associate a name to a zettel identifier.
For example, if your application is named ""app"", you create a metadata key ''app-zid''.
Its value is the zettel identifier of the zettel that configures your application.
=== Reserved Zettel Identifier
|=From|=To|=Description
|00000000000000|0000000000000|This is an invalid zettel identifier
|00000000000001|0000099999999|[[Predefined zettel|00001005090000]]
|00001000000000|0000109999999|This [[Zettelstore manual|00001000000000]]
|00001100000000|0000899999999|Reserved, do not use.
|00009000000000|0000999999999|Reserved for applications (legacy)
Since the format of zettel identifier will change in the near future, no external application is allowed to use the range ''00000000000001'' … ''0000999999999''.
==== External Applications (Legacy)
|=From|=To|=Description
|00009000001000|00009000001999|[[Zettel Presenter|https://zettelstore.de/contrib]], an application to display zettel as a HTML-based slideshow