title: Reserved zettel identifier
role: manual
tags: #design #manual #zettelstore
syntax: zmk

[[Zettel identifier|00001006050000]] are typically created by examine the current date and time.
By renaming the name of the underlying zettel file, you are able to 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 ''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|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 Identifier

|= 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 a HTML-based slideshow