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: 00000999999999 00001000000000 00001004020000 00001005090000 00001006050000
lang: en
license: EUPL-1.2-or-later
modified: 20250627152022
published: 20250627152022
visibility: public

[[Zettel identifiers|00001006050000]] are typically created based on the current date and time.
By renaming the underlying zettel files, you can provide any sequence of 14 digits.

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 is ''00010000000000''.
But you can [[configure|00001004020000#home-zettel]] another zettel with another identifier as the new home zettel.].
Zettel identifiers of this manual have been chosen to begin with ''000010''.

However, some external applications may need at least one defined zettel identifier to work properly.
Zettel [[Zettelstore Application Directory|00000999999999]] (''00000999999999'') 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 Identifiers
|= From|=To|=Description
|00000000000000|00000000000000|This is an invalid zettel identifier
|00000000000001|00000999999999|[[Predefined zettel|00001005090000]]
|00001000000000|00001099999999|This [[Zettelstore manual|00001000000000]]
|00001100000000|00008999999999|Reserved, do not use
|00009000000000|00009999999999|Reserved for applications
==== External Applications
|= From|=To|=Description
|00009000001000|00009000001999|[[Zettel Presenter|https://zettelstore.de/contrib]], an application to display zettel as an HTML-based slideshow