If something is case-sensitive, it means that it will differentiate between lowercase and uppercase characters.
In the Voucherify context, case-sensitive codes mean that the validation process will differentiate between lowercase, uppercase, or mixed codes. For example, a standalone code “BLACKFRIDAY” would be treated as separate from “blackfriday”. Voucherify-generated codes are case-sensitive by default, but you can change this setting. Note that you need to change that before creating new projects and campaigns as it cannot be modified later on for already existing codes and campaigns.
When to use case-sensitivity?
Case-sensitive codes are better suited for unique coupon codes that should be copied and pasted as they are usually not easy to remember. In that case, the case-sensitive code helps you to prevent fraud (it is harder to hack a code that is case-sensitive). Standalone codes, on the other hand, should be case-insensitive, letting customers use any variant of the code regardless of the casing.