[role="xpack"]
[[security-api-clear-cache]]
=== Clear cache API
++++
<titleabbrev>Clear cache</titleabbrev>
++++

Evicts users from the user cache. You can completely clear
the cache or evict specific users.

[[security-api-clear-request]]
==== {api-request-title}

`POST /_security/realm/<realms>/_clear_cache` +

`POST /_security/realm/<realms>/_clear_cache?usernames=<usernames>`


[[security-api-clear-desc]]
==== {api-description-title}

User credentials are cached in memory on each node to avoid connecting to a
remote authentication service or hitting the disk for every incoming request.
There are realm settings that you can use to configure the user cache. For more
information, see
{stack-ov}/controlling-user-cache.html[Controlling the user cache].

To evict roles from the role cache, see the 
<<security-api-clear-role-cache,Clear roles cache API>>.

[[security-api-clear-path-params]]
==== {api-path-parms-title}

`realms`::
  (Required, list) A comma-separated list of the realms to clear.

`usernames`::
  (Optional, list) A comma-separated list of the users to clear from the cache.
  If you do not specify this parameter, the API evicts all users from the user
  cache.

[[security-api-clear-example]]
==== {api-examples-title}

For example, to evict all users cached by the `file` realm:

[source,console]
--------------------------------------------------
POST /_security/realm/default_file/_clear_cache
--------------------------------------------------

To evict selected users, specify the `usernames` parameter:

[source,console]
--------------------------------------------------
POST /_security/realm/default_file/_clear_cache?usernames=rdeniro,alpacino
--------------------------------------------------

To clear the caches for multiple realms, specify the realms as a comma-delimited
list:

[source,console]
------------------------------------------------------------
POST /_security/realm/default_file,ldap1/_clear_cache
------------------------------------------------------------