# \Api20100401UserDefinedMessageApi
All URIs are relative to *https://api.twilio.com*
[**create_user_defined_message**](Api20100401UserDefinedMessageApi.md#create_user_defined_message) | **POST** /2010-04-01/Accounts/{AccountSid}/Calls/{CallSid}/UserDefinedMessages.json |
## create_user_defined_message
> models::ApiPeriodV2010PeriodAccountPeriodCallPeriodUserDefinedMessage create_user_defined_message(account_sid, call_sid, content, idempotency_key)
Create a new User Defined Message for the given Call SID.
### Parameters
**account_sid** | **String** | The SID of the [Account](https://www.twilio.com/docs/iam/api/account) that created User Defined Message. | [required] |
**call_sid** | **String** | The SID of the [Call](https://www.twilio.com/docs/voice/api/call-resource) the User Defined Message is associated with. | [required] |
**content** | **String** | The User Defined Message in the form of URL-encoded JSON string. | [required] |
**idempotency_key** | Option<**String**> | A unique string value to identify API call. This should be a unique string value per API call and can be a randomly generated. | |
### Return type
[**models::ApiPeriodV2010PeriodAccountPeriodCallPeriodUserDefinedMessage**](api.v2010.account.call.user_defined_message.md)
### Authorization
[accountSid_authToken](../README.md#accountSid_authToken)
### HTTP request headers
- **Content-Type**: application/x-www-form-urlencoded
- **Accept**: application/json
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