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Feature flags

Feature flags enable you to easily toggle features on and off, conduct A/B testing, gradually roll out new functionality, and personalize user experiences — all without the need for extensive code deployments. With feature flags, you can empower your team to make dynamic changes, iterate quickly, and deliver enhanced user experiences with ease.

A flag is simply a fork somewhere in your code. Where originally there was a single code path, the presence of a flag creates a gate that splits that path into two or more code paths. In its most basic form a flag object can represented by a human readable name, a key, and a status (on/off). Here's a quick example:

# Before, price is $10 for everyone.

price_of_shoes = 10

The presence of a feature flag unlocks multiple paths:

# After, show different prices to different users based on a flag.

group = get_string_assignment('pricing_gate', user_id, user_attributes, 'do_not_round_down')

if (group == "round_down_to_cents"):
    price_of_shoes = 9.99
else:
    price_of_shoes = 10

Concepts​

The following are the central feature flagging concepts in Eppo:

Use cases​

Feature flags are applicable for a number of use cases: