# cPanel API 2 Functions - SubDomain::validregex

Warning:
The cPanel API 2 system is deprecated. We **strongly** recommend that you use [UAPI](/cpanel/introduction) instead of cPanel API 2.

## Description

This function returns a regular expression to use to validate a subdomain.

Warning:
We **strongly** recommend that you use [UAPI](/cpanel/introduction/) instead of cPanel API 2. However, no equivalent UAPI function exists.

## Examples

WHM API (JSON)


```undefined syntaxhighlighter-pre
https://hostname.example.com:2087/cpsess###########/json-api/cpanel?cpanel_jsonapi_user=user&cpanel_jsonapi_apiversion=2&cpanel_jsonapi_module=SubDomain&cpanel_jsonapi_func=validregex
```

Note:
For more information, read our [Calls from the WHM API](/whm/use-whm-api-to-call-cpanel-api-and-uapi) documentation.

LiveAPI PHP Class


```undefined syntaxhighlighter-pre
$cpanel = new CPANEL(); // Connect to cPanel - only do this once.

// Return a regex.
$validregex = $cpanel->api2(
    'SubDomain', 'validregex'
);
```

Note:
For more information, read our [Guide to the LiveAPI System](/guides/guide-to-the-liveapi-system/#guide-to-the-liveapi-system).

LiveAPI Perl Module


```undefined syntaxhighlighter-pre
my $cpliveapi = Cpanel::LiveAPI->new(); # Connect to cPanel - only do this once.

# Return a regex.
my $validregex = $cpliveapi->api2(
    'SubDomain', 'validregex',
);
```

Note:
For more information, read our [Guide to the LiveAPI System](/guides/guide-to-the-liveapi-system/#guide-to-the-liveapi-system).

cPanel Tag System (deprecated)

Warnings:
- cPanel tags are **deprecated**. We **strongly** recommend that you **only** use the [LiveAPI](/guides/guide-to-the-liveapi-system) system to call the cPanel APIs. Examples are **only** present in order to help developers move from the old cPanel tag system to our [LiveAPI](/guides/guide-to-the-liveapi-system).
- cPanel API 2 calls that use cPanel tags vary in code syntax and in their output.
- For more information, read our [Deprecated cPanel Tag Usage](/cpanel-api-2/cpanel-api-2-deprecate-cpanel-tag-usage/) documentation.


Command Line


```undefined syntaxhighlighter-pre
cpapi2 --user=username SubDomain validregex
```

div
Notes:

- You **must** URI-encode values.
- `username` represents your account-level username.
- You **must** include the `--user=username` option.
- For more information and additional output options, read our [Guide to cPanel API 2](/cpanel-api-2/) documentation or run the `cpapi2 --help` command.
- If you run CloudLinux™, you **must** use the full path of the `cpapi2` command:

```undefined syntaxhighlighter-pre
/usr/local/cpanel/bin/cpapi2
```


br
Output (JSON)


```undefined syntaxhighlighter-pre
{
  "cpanelresult": {
    "apiversion": 2,
    "func": "validregex",
    "data": [
      "^\\*$|^(?:\\*\\.)?[\\da-zA-Z](?:[-\\da-zA-Z]*[\\da-zA-Z])?(?:\\.[\\da-zA-Z](?:[-\\da-zA-Z]*[\\da-zA-Z])?)*$"
    ],
    "event": {
      "result": 1
    },
    "module": "SubDomain"
  }
}
```

Note:
Use cPanel's *[API Shell](https://docs.cpanel.net/cpanel/advanced/api-shell-for-cpanel)* interface (*cPanel >> Home >> Advanced >> API Shell*) to directly test cPanel API calls.

## Parameters

This function does not accept parameters.

## Returns

table
thead
tr
th
strong
Return
th
strong
Type
th
strong
Description
th
strong
Possible values
th
strong
Example
tbody
tr
td
code
data
td
em
array
td
span
A
a
Perl Compatible Regular Expression (PCRE)
 that the system uses to validate the subdomain.
td
A valid PCRE.
td
code
^\\*$|^(?:\\*\\.)?[\\da-zA-Z](?:[-\\da-zA-Z]*[\\da-zA-Z])?(?:\\.[\\da-zA-Z](?:[-\\da-zA-Z]*[\\da-zA-Z])?)*$
tr
td
code
reason
td
em
string
td
div
p
A reason for failure.
p
This function only returns a 
code
reason
 value if there was an error.
td
A string that describes the error.
td
code
This is an error message.
tr
td
code
result
td
em
Boolean
td
p
Whether the function succeeded.
td
ul
li
code
1
 — Success.
li
code
0
 — Failure.
td
code
1