[[indices-alias-exists]]
=== Index alias exists API
++++
<titleabbrev>Index alias exists</titleabbrev>
++++

Checks if an index alias exists.

//tag::index-alias-def[]
An index alias is a secondary name
used to refer to one or more existing indices.
//end::index-alias-def[]

The returned HTTP status code indicates whether the index alias exists or not.
A `404` means it does not exist,
and `200` means it does.

[source,js]
----
HEAD /_alias/alias1
----
// CONSOLE
// TEST[setup:twitter]
// TEST[s/^/PUT twitter\/_alias\/alias1\n/]


[[alias-exists-api-request]]
==== {api-request-title}

`HEAD /_alias/<alias>`

`HEAD /<index>/_alias/<alias>`


[[alias-exists-api-path-params]]
==== {api-path-parms-title}

`<alias>`::
(Required, string)
Comma-separated list or wildcard expression of index alias names
used to limit the request.

include::{docdir}/rest-api/common-parms.asciidoc[tag=index]

[[alias-exists-api-query-params]]
==== {api-query-parms-title}

include::{docdir}/rest-api/common-parms.asciidoc[tag=allow-no-indices]

include::{docdir}/rest-api/common-parms.asciidoc[tag=expand-wildcards]
+
Defaults to `all`.

include::{docdir}/rest-api/common-parms.asciidoc[tag=index-ignore-unavailable]

include::{docdir}/rest-api/common-parms.asciidoc[tag=local]


[[alias-exists-api-response-codes]]
==== {api-response-codes-title}

`200`::
Indicates all specified index aliases exist.

 `404`::
Indicates one or more specified index aliases **do not** exist.


[[alias-exists-api-example]]
==== {api-examples-title}

[source,js]
----
HEAD /_alias/2030
HEAD /_alias/20*
HEAD /logs_20302801/_alias/*
----
// CONSOLE
// TEST[s/^/PUT logs_20302801\nPUT logs_20302801\/_alias\/2030\n/]
