Joker badge depends on the player level as follows:

• Accounts from Level 60 to 69 receive the bronze Badge.
• Accounts from Level 70 to 79 receive the silver badge.
• Accounts from Level 80 to 89 receive the gold badge.
• Accounts above Level 90 receive the ruby badge.

Please click the following link for more details about the badges you can earn and their requirements:
https://blog.jawaker.com/jawakerbadges-en/