# CreateRegexMatchSet
**Note**
AWS WAF Classic support will end on September 30, 2025.
This is ** AWS WAF Classic** documentation. For more information, see [AWS WAF Classic](https://docs.aws.amazon.com/waf/latest/developerguide/classic-waf-chapter.html) in the developer guide.
**For the latest version of AWS WAF **, use the AWS WAFV2 API and see the [AWS WAF Developer Guide](https://docs.aws.amazon.com/waf/latest/developerguide/waf-chapter.html). With the latest version, AWS WAF has a single set of endpoints for regional and global use.
Creates a [RegexMatchSet](API_waf_RegexMatchSet.md). You then use [UpdateRegexMatchSet](API_waf_UpdateRegexMatchSet.md) to identify the part of a web request that you want AWS WAF to inspect, such as the values of the `User-Agent` header or the query string. For example, you can create a `RegexMatchSet` that contains a `RegexMatchTuple` that looks for any requests with `User-Agent` headers that match a `RegexPatternSet` with pattern `B[a@]dB[o0]t`. You can then configure AWS WAF to reject those requests.
To create and configure a `RegexMatchSet`, perform the following steps:
1. Use [GetChangeToken](API_waf_GetChangeToken.md) to get the change token that you provide in the `ChangeToken` parameter of a `CreateRegexMatchSet` request.
1. Submit a `CreateRegexMatchSet` request.
1. Use `GetChangeToken` to get the change token that you provide in the `ChangeToken` parameter of an `UpdateRegexMatchSet` request.
1. Submit an [UpdateRegexMatchSet](API_waf_UpdateRegexMatchSet.md) request to specify the part of the request that you want AWS WAF to inspect (for example, the header or the URI path) and the value, using a `RegexPatternSet`, that you want AWS WAF to watch for.
For more information about how to use the AWS WAF API to allow or block HTTP requests, see the [AWS WAF Developer Guide](https://docs.aws.amazon.com/waf/latest/developerguide/).
## Request Syntax
```
{
"ChangeToken": "string",
"Name": "string"
}
```
## Request Parameters
For information about the parameters that are common to all actions, see [Common Parameters](CommonParameters.md).
The request accepts the following data in JSON format.
** [ChangeToken](#API_waf_CreateRegexMatchSet_RequestSyntax) **
The value returned by the most recent call to [GetChangeToken](API_waf_GetChangeToken.md).
Type: String
Length Constraints: Minimum length of 1. Maximum length of 128.
Pattern: `.*\S.*`
Required: Yes
** [Name](#API_waf_CreateRegexMatchSet_RequestSyntax) **
A friendly name or description of the [RegexMatchSet](API_waf_RegexMatchSet.md). You can't change `Name` after you create a `RegexMatchSet`.
Type: String
Length Constraints: Minimum length of 1. Maximum length of 128.
Pattern: `.*\S.*`
Required: Yes
## Response Syntax
```
{
"ChangeToken": "string",
"RegexMatchSet": {
"Name": "string",
"RegexMatchSetId": "string",
"RegexMatchTuples": [
{
"FieldToMatch": {
"Data": "string",
"Type": "string"
},
"RegexPatternSetId": "string",
"TextTransformation": "string"
}
]
}
}
```
## Response Elements
If the action is successful, the service sends back an HTTP 200 response.
The following data is returned in JSON format by the service.
** [ChangeToken](#API_waf_CreateRegexMatchSet_ResponseSyntax) **
The `ChangeToken` that you used to submit the `CreateRegexMatchSet` request. You can also use this value to query the status of the request. For more information, see [GetChangeTokenStatus](API_waf_GetChangeTokenStatus.md).
Type: String
Length Constraints: Minimum length of 1. Maximum length of 128.
Pattern: `.*\S.*`
** [RegexMatchSet](#API_waf_CreateRegexMatchSet_ResponseSyntax) **
A [RegexMatchSet](API_waf_RegexMatchSet.md) that contains no `RegexMatchTuple` objects.
Type: [RegexMatchSet](API_waf_RegexMatchSet.md) object
## Errors
For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).
** WAFDisallowedNameException **
The name specified is invalid.
HTTP Status Code: 400
** WAFInternalErrorException **
The operation failed because of a system problem, even though the request was valid. Retry your request.
HTTP Status Code: 500
** WAFLimitsExceededException **
The operation exceeds a resource limit, for example, the maximum number of `WebACL` objects that you can create for an AWS account. For more information, see [AWS WAF Classic quotas](https://docs.aws.amazon.com/waf/latest/developerguide/classic-limits.html) in the * AWS WAF Developer Guide*.
HTTP Status Code: 400
** WAFStaleDataException **
The operation failed because you tried to create, update, or delete an object by using a change token that has already been used.
HTTP Status Code: 400
## See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following:
+ [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/waf-2015-08-24/CreateRegexMatchSet)
+ [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/waf-2015-08-24/CreateRegexMatchSet)