# Mission Sticker API
The functions described in this document can only be used by corporate users who have submitted the required applications. To use it with your LINE Official Account, contact your sales representative or contact our Sales partners (opens new window).
Mission stickers are provided to user upon completion of certain objectives. Using the sicker as an incentive, users can be encouraged to "link ID information", "register as a member", or "answer a questionnaire".
# API reference
For more information on the API specifications, refer to "Mission Sticker API" in the "Option API reference for corporate users".
# When users cannot download a mission sticker
If a user can't download a mission sticker set even though the API call is successful, check the following. For more information, contact your LINE representative.
- The sticker set information including the release date, channel ID, and country is accurate.
- The country of the user is the same as that of the sticker set.
- Target user has already downloaded a mission sticker.