# Users are notified of coupons

Users in WeChat initiated the coupon operation, will take the initiative to call back the business to receive coupons, businesses need to be based on their own coupon inventory, etc., return a specific coupon results. If the merchant returns successfully, the platform side will record the returned user coupons, in order to avoid record failure due to network exceptions, etc. It is suggested that merchants call the "add user coupon" interface when the coupon is successful, and the platform side will ensure the uniqueness according to the merchant side coupon ID returned by the merchant and the merchant side user coupon ID; It is also recommended to call the "Update coupon inventory" interface for inventory updates.

# Example of callback request parameters

Depending on the data format (json or xml) set by the merchant, take xml as an example

<xml>
    <ToUserName>gh_abcdefg</ToUserName> 
    <FromUserName>oABCD</FromUserName> 
    <CreateTime>12344555555</CreateTime>
    <MsgType>event</MsgType> 
    <Event>open_product_receive_coupon</Event>
    <out_coupon_id>real_out_coupon_id</out_coupon_id>
    <request_id>real_request_id</request_id>
</xml>

# Example of a callback callback

Depending on the data format (json or xml) set by the merchant, take xml as an example

<xml> 
  <out_user_coupon_id>real_out_user_coupon_id</out_user_coupon_id>  
  <request_id>real_request_id</request_id>  
  <ret_code>0</ret_code>
  <ret_msg>ok</ret_msg>
  <out_coupon_id>real_out_coupon_id</out_coupon_id> 
</xml>

# Dxplaination of callback request parameters

# Dxplaination of callback callback parameters

# Error message displayed when WeChat Channels scene coupons cannot be redeemed