The API (short for ""**A**pplication **P**rogramming **I**nterface"") is the primary way to communicate with a running Zettelstore.
Most integration with other systems and services is performed via the API.
The [[web user interface|00001014000000]] is just an alternative, secondary way of interacting with a Zettelstore.

=== Background
The API is HTTP-based and uses plain text and [[symbolic expressions|00001012930000]] as its main encoding formats for exchanging messages between a Zettelstore and its client software.

There is an [[overview zettel|00001012920000]] that shows the structure of the endpoints used by the API and gives an indication about its use.

=== Authentication
If [[authentication is enabled|00001010040100]], most API calls must include an [[access token|00001010040700]] that proves the identity of the caller.
* [[Authenticate a user|00001012050200]] to obtain an access token
* [[Renew an access token|00001012050400]] without costly re-authentication
* [[Provide an access token|00001012050600]] when doing an API call

=== Zettel lists
* [[List all zettel|00001012051200]]
* [[Query the list of all zettel|00001012051400]]
* [[Determine a tag zettel|00001012051600]]
* [[Determine a role zettel|00001012051800]]

=== Working with zettel
* [[Create a new zettel|00001012053200]]
* [[Retrieve metadata and content of an existing zettel|00001012053300]]
* [[Retrieve metadata of an existing zettel|00001012053400]]
* [[Retrieve evaluated metadata and content of an existing zettel in various encodings|00001012053500]]
* [[Retrieve parsed metadata and content of an existing zettel in various encodings|00001012053600]]
* [[Retrieve references of an existing zettel|00001012053800]]
* [[Update metadata and content of a zettel|00001012054200]]
* [[Delete a zettel|00001012054600]]

=== Various helper methods
* [[Retrieve administrative data|00001012070500]]
* [[Execute some commands|00001012080100]]
** [[Check for authentication|00001012080200]]
** [[Refresh internal data|00001012080500]]