[[Zettel identifier|00001006050000]] are typically created by examine the current date and time.
By renaming a zettel, you are able to provide any sequence of 14 digits.
If no other zettel has the same identifier, you are allowed to rename a zettel.

To make things easier, you normally should 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 a range of specific zettel identifier to work properly.
Identifier that begin with ''00009'' can be used for such purpose.
To request a reservation, please send an email to the maintainer of Zettelstore.
The request must include the following data:
; Title
: Title of you application
; Description
: A brief description what the application is used for and why you need to reserve some zettel identifier
; Number
: Specify the amount of zettel identifier you are planning to use.
Minimum size is 100.
If you need more than 10.000, your justification will contain more words.
=== Reserved Zettel Identifier
|=From|=To|=Description
|00000000000000|0000000000000|This is an invalid zettel identifier
|00000000000001|0000009999999|[[Predefined zettel|00001005090000]]
|00000100000000|0000019999999|This [[Zettelstore manual|00001000000000]]
|00000200000000|0000899999999|Reserved for future use
|00009000000000|0000999999999|Reserved for applications
This list may change in the future.
==== External Applications
|=From|=To|=Description
|00009000001000|00009000001999|[[Zettel Presenter|https://zettelstore.de/contrib]], an application to display zettel as a HTML-based slideshow
|00009000002000|00009000002999|[[Zettel Blog|https://zettelstore.de/contrib]], an application to collect and transform zettel into a blog