# Using audiences
Audiences are a feature to perform advanced targeting.
By creating an audience, you can send messages to users who opened a message or clicked a URL in a message.
Only Japanese (JP), Thai (TH), and Taiwanese (TW) users with LINE Official Accounts can create audiences.
You must complete some additional application forms before you can use IFAs to specify recipients. For more information, contact your LINE representative or submit an inquiry through the LINE for Business website.
# Creating audiences
You can create the following audiences with Messaging API.
|Audience for uploading user IDs||A set of users that can be identified by user IDs or IFA (Identifier For Advertisers)|
|Audience for click-based retargeting||A set of users that clicked a URL in a message sent in the past|
|Audience for impression-based retargeting||A set of users that opened a message sent in the past|
# Using audiences
You can use audiences you have created to send narrowcast messages. For more details, see Sending messages to multiple users via attribute data or retargeting (narrowcast messages).
# About audience sharing
If you don't use audience sharing, change your audience's authority level to
PRIVATE. To learn more about changing audience's authority levels, see Change the authority level of the audience in the Messaging API reference.
# About audience's specifications
Audience's specifications are as follows:
|The number of audiences per channel||Maximum 1000|
|Retention period of an audience||Up to 180 days|
|The number of user IDs or IFAs you can upload to an audience for uploading user IDs per request||Maximum 10000|
|The number of users per audience|
|The period during which the retargeting audience* can be created after the message is sent||Maximum 60 days|
*Audience for click-based retargeting and audience for impression-based retargeting.
Learn more from Usage restrictions of narrowcast messages.