Types of filters
Sanitize filters
Types of filters
PHP Manual

## Validate filters

Listing of filters for validation
ID | Name | Options | Flags | Description
--- | --- | --- | --- | ---
`FILTER_VALIDATE_BOOLEAN` | "boolean" |  | `FILTER_NULL_ON_FAILURE` | Returns `TRUE` for "1", "true", "on" and "yes". Returns `FALSE` otherwise. If `FILTER_NULL_ON_FAILURE` is set, `FALSE` is returned only for "0", "false", "off", "no", and "", and `NULL` is returned for all non-boolean values.
`FILTER_VALIDATE_EMAIL` | "validate_email" |  |  | Validates value as e-mail.
`FILTER_VALIDATE_FLOAT` | "float" | `decimal` | `FILTER_FLAG_ALLOW_THOUSAND` | Validates value as float.
`FILTER_VALIDATE_INT` | "int" | `min_range`, `max_range` | `FILTER_FLAG_ALLOW_OCTAL`, `FILTER_FLAG_ALLOW_HEX` | Validates value as integer, optionally from the specified range.
`FILTER_VALIDATE_IP` | "validate_ip" |  | `FILTER_FLAG_IPV4`, `FILTER_FLAG_IPV6`, `FILTER_FLAG_NO_PRIV_RANGE`, `FILTER_FLAG_NO_RES_RANGE` | Validates value as IP address, optionally only IPv4 or IPv6 or not from private or reserved ranges.
`FILTER_VALIDATE_REGEXP` | "validate_regexp" | `regexp` |  | Validates value against `regexp`, a Perl-compatible regular expression.

`FILTER_VALIDATE_URL`

"validate_url"

`FILTER_FLAG_PATH_REQUIRED`, `FILTER_FLAG_QUERY_REQUIRED`

Validates value as URL (according to » http://www.faqs.org/rfcs/rfc2396), optionally with required components. Beware a valid URL may not specify the HTTP protocol `http://` so further validation may be required to determine the URL uses an expected protocol, e.g. `ssh://` or `mailto:`. Note that the function will only find ASCII URLs to be valid; internationalized domain names (containing non-ASCII characters) will fail.

> Note:

> Numbers +0 and -0 are not valid integers but validate as floats.