Authentication for future API calls is done by sending a [[user identification|00001010040200]] and a password to the Zettelstore to obtain an [[access token|00001010040700]].
This token has to be used for other API calls.
It is valid for a relatively short amount of time, as configured with the key ''token-lifetime-api'' of the [[startup configuration|00001004010000#token-lifetime-api]] (typically 10 minutes).

The simplest way is to send user identification (''IDENT'') and password (''PASSWORD'') via [[HTTP Basic Authentication|https://tools.ietf.org/html/rfc7617]] and send them to the [[endpoint|00001012920000]] ''/a'' with a POST request:
```{="sh"}
# curl -X POST -u IDENT:PASSWORD http://127.0.0.1:23123/a
("Bearer" "eyJhbGciOiJIUzUxMiJ9.eyJfdGsiOjEsImV4cCI6MTY4MTMwNDA2MiwiaWF0IjoxNjgxMzA0MDAyLCJzdWIiOiJvd25lciIsInppZCI6IjIwMjEwNjI5MTYzMzAwIn0.kdF8PdiL50gIPkRD3ovgR6nUXR0-80EKAXcY2zVYgYvryF09iXnNR3zrvYnGzdrArMcnvAYqVvuXtqhQj2jG9g" 600)
```
Some tools, like [[curl|https://curl.haxx.se/]], also allow to specify user identification and password as part of the URL:
```{="sh"}
# curl -X POST http://IDENT:PASSWORD@127.0.0.1:23123/a
("Bearer" "eyJhbGciOiJIUzUxMiJ9.eyJfdGsiOjEsImV4cCI6MTY4MTMwNDA4NiwiaWF0IjoxNjgxMzA0MDI2LCJzdWIiOiJvd25lciIsInppZCI6IjIwMjEwNjI5MTYzMzAwIn0.kZd3prYc79dt9efDsrYVHtKrjWyOWvfByjeeUB3hf_vs43V3SNJqmb8k-zTHVNWOK0-5orVPrg2tIAqbXqmkhg" 600)
```
If you do not want to use Basic Authentication, you can also send user identification and password as HTML form data:
```{="sh"}
# curl -X POST -d 'username=IDENT&password=PASSWORD' http://127.0.0.1:23123/a
("Bearer" "eyJhbGciOiJIUzUxMiJ9.eyJfdGsiOjEsImV4cCI6MTY4MTMwNDA4OCwiaWF0IjoxNjgxMzA0MDI4LCJzdWIiOiJvd25lciIsInppZCI6IjIwMjEwNjI5MTYzMzAwIn0.qIEyOMFXykCApWtBaqbSESwTL96stWl2LRICiRNAXUjcY-mwx_SSl9L5Fj2FvmrI1K1RBvWehjoq8KZUNjhJ9Q" 600)
```
In all cases, you will receive a list with three elements that will contain all [[relevant data|00001012921000]] to be used for further API calls.

**Important:** obtaining a token is a time-intensive process.
Zettelstore will delay every request to obtain a token for a certain amount of time.
Please take into account that this request will take approximately 500 milliseconds, under certain circumstances more.

However, if [[authentication is not enabled|00001010040100]] and you send an authentication request, no user identification/password checking is done and you receive an artificial token immediate, without any delay:
```{="sh"}
# curl -X POST -u IDENT:PASSWORD http://127.0.0.1:23123/a
("Bearer" "freeaccess" 316224000)
```
In this case, it is even possible to omit the user identification/password.
=== HTTP Status codes
In all cases of successful authentication, a list is returned, which contains the token as the second element.
A successful authentication is signaled with the HTTP status code 200, as usual.

Other status codes possibly send by the Zettelstore:
; ''400''
: Unable to process the request.
In most cases the form data was invalid.
; ''401''
: Authentication failed.
Either the user identification is invalid or you provided the wrong password.
; ''403''
: Authentication is not active.