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Flag variations

Variations are the distinct paths that can be taken from a single flag. In the simplest case a flag will have two variations, but there is no limit.

As a simple example, consider a feature flag that controls the button color of the "Buy Now" button on the checkout page. In this case, the feature flag may be called checkout_page_buy_now_button_color and the variations could be red, green and yellow.

Eppo flags support multiple types: boolean, string, numeric, and JSON.

Flag types

Boolean flags​

Boolean flags can only ever have two variants, each corresponding to a true or false value. We recommend setting boolean flags to true when the flag is on and false when the flag is off.

String flags​

String flags are the default and cover most use cases.

String flags have a limit of 65KB. Strings are UTF-8 encoded, so certain characters, like emojis and non-ASCII characters, take more than one byte each.

You can use escape sequences in string flag values.

Numeric flags​

Numeric flags are recommended when you want to target variations based on dates, timeouts, or other numerical operations.

Numeric flags can be either an integer or a floating-point type. Eppo will show an error message in the UI if a variation value is not a numeric type.

JSON flags​

JSON flags allow you to send a map of values. This can be helpful to change the user experience without needing to deploy code.

You can write an empty array as {} if there is no property value present for a variation.

JSON object and array flags have a size limit of 32KB.

Eppo will show an error message in the UI if a variation value does not validate as proper JSON.