Is there a default set of stickers available?

We don’t have a default set of stickers. We do support UTF emojis though (but cannot guarantee that your clients’ devices support them).

Implementing stickers can easily be done if you utilize the “data” field when sending a message. The “data” field can be any string data such as json/xml. Use this field to send “meta” information of each sticker, then render a corresponding sticker from each client.