Core concepts

A quick mental model for how Vexil fits together — so the rest of the docs make sense.

Organization

Your workspace. All flags, environments, teammates, and experiments belong to one org. You can belong to multiple orgs and switch between them from the sidebar.

Environment

A named deployment target — e.g. Production, Staging, Development. Each flag has independent state per environment: enabled/disabled, rollout percentage, and value overrides.

Feature flag

A named key that resolves to a value at runtime. The SDK evaluates the flag against the current environment and returns the appropriate value for that user.

Experiment

Ties a flag to a goal event. Vexil tracks which variant each user sees (impressions) and which ones lead to the goal (conversions), then shows you per-variant conversion rates.

Dependency

A relationship between two flags: "Flag B only works when Flag A is enabled." Vexil prevents circular dependencies and offers cascade-disable to keep state consistent.

API key

A secret your SDK uses to identify your organization. Create one in Settings → API Keys. Each key is scoped to one org — no extra config needed.