Bonus codes, sometimes also known as promo codes or voucher codes, are codes used by online casinos to award bonuses to players. Bonus codes are usually related to a specific promotion, and can be used when registering to claim the bonus. Bonuses can be in the form of free spins, no-deposit bonuses, welcome bonuses or deposit match bonuses.
When a bonus code is used to claim a bonus, it typically has to be entered in the cashier or registration page when signing up. Some casinos even have specific parts of their websites dedicated to bonus codes that can be used to activate featured promotions.