All API endpoints conform to the pattern ''[PREFIX]LETTER[/ZETTEL-ID]'', where:
; ''PREFIX''
: is the URL prefix (default: ""/""), configured via the ''url-prefix'' [[startup configuration|00001004010000]],
; ''LETTER''
: is a single letter that specifies the resource type,
; ''ZETTEL-ID''
: is an optional 14 digits string that uniquely [[identify a zettel|00001006050000]].
The following letters are currently in use:
|=Letter:|=Without zettel identifier|=With [[zettel identifier|00001006050000]]|=Mnemonic
|''a''|POST: [[client authentication|00001012050200]]||**A**uthenticate
||PUT: [[renew access token|00001012050400]]||
|''x''|GET: [[retrieve administrative data|00001012070500]]||E**x**ecute
||POST: [[execute command|00001012080100]]||
|''z''|GET: [[list zettel|00001012051200]]/[[query zettel|00001012051400]]|GET: [[retrieve zettel|00001012053300]]|**Z**ettel
||POST: [[create new zettel|00001012053200]]|PUT: [[update zettel|00001012054200]]|
|||DELETE: [[delete zettel|00001012054600]]|
|||MOVE: [[rename zettel|00001012054400]]|
The full URL will contain either the ""http"" oder ""https"" scheme, a host name, and an optional port number.

The API examples will assume the ""http"" schema, the local host ""127.0.0.1"", the default port ""23123"", and the default empty ''PREFIX'' ""/"".
Therefore, all URLs in the API documentation will begin with ""http://127.0.0.1:23123/"".