How to Write Feature Flag Targeting Rules

Targeting rules match on context attributes (plan, region, user id) so a flag enables only for the audience you choose.

A targeting rule enables a variation when the evaluation context matches conditions. Pass a consistent context (user key plus attributes) so rules resolve the same way in app and CI.

Steps

Decide the attributes rules will match on (plan, country, user id).
Write ordered rules; the first match wins, else the default.
Pass those attributes in the evaluation context everywhere.

Targeting rules

flags.yaml

flags:
  new-checkout:
    defaultVariation: false
    rules:
      - if: { attribute: plan, op: in, values: [enterprise] }
        variation: true
      - if: { attribute: country, op: equals, value: CA }
        variation: true

Evaluate with context

Terminal

const on = await client.getBooleanValue('new-checkout', false, {
  targetingKey: user.id,
  plan: user.plan,
  country: user.country,
});

Gotchas

Missing attributes make a rule fall through to the default; always pass the full context.
Rule order matters; put the most specific rules first.