Environment Overrides

Overview

All backend SDKs support overriding flag values using environment variables. This is useful for local development, testing, and CI environments where you want to control flags without changing them in the dashboard.

How It Works

Set an environment variable with the FLAGS_ prefix followed by the flag name in uppercase:

export FLAGS_MY_FEATURE=true
export FLAGS_BETA_MODE=false

When you check a flag, the SDK checks environment variables before checking the API or cache. If a matching environment variable exists, its value is used immediately.

Name Normalization

Flag names are normalized to match environment variable names. All of these refer to the same flag:

Environment Variable	Matches Flag Names
FLAGS_MY_FEATURE	my-feature, my_feature, my feature
FLAGS_DARK_MODE	dark-mode, dark_mode, dark mode

The normalization converts hyphens, underscores, and spaces to a common form and ignores case.

Accepted Values

Truthy values

true, 1, on, yes, enabled

Falsy values

false, 0, off, no, disabled

Priority Order

Flags are resolved in this order (highest priority first):

1. Environment variable (FLAGS_*)
2. Cached value (from API response)
3. Default (false / disabled)

Examples

Local development

# Enable a feature only on your machine
FLAGS_NEW_CHECKOUT=true go run ./cmd/server

CI/CD

# Disable analytics in test environment
FLAGS_ANALYTICS=false pytest tests/

Docker

ENV FLAGS_MAINTENANCE_MODE=false

docker-compose.yml

services:
  app:
    environment:
      - FLAGS_BETA_FEATURE=true