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A flag is a named toggle or value that your application reads at runtime. Every flag has:
  • A key — the developer-facing identifier (e.g. new-checkout-flow). Immutable after creation.
  • A type — boolean, string, or number. Determines what values the flag can return.
  • A config per environment — flags are independently controlled in each of your environments.

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Flag types

TypeDefault valueExample use
booleantrue / falseFeature on/off
stringAny stringA/B copy, theme name, API endpoint
numberAny numberRate limit, sample rate, price

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clientSafe

By default, flags are only accessible to server API keys. Setting clientSafe: true allows the flag to be included in the public bundle fetched by browser SDKs (client API keys). Only mark a flag clientSafe if its value carries no sensitive business logic — client-side code is readable by end users.

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Archiving

Setting archived: true marks the flag as inactive. Archived flags are hidden in the dashboard by default but remain in the database and are still returned by the API unless filtered out.

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Versions

Flag state is append-only. Every change to a flag’s config in an environment creates a new flag_version row — previous versions are never mutated. This is what powers the audit trail and change proposals. See Flag Config for the full config schema.