Getting started
Targeting rules
Rules let you serve different flag values to different users. They're evaluated in order — the first rule that matches wins, and everything else falls through to the default.
Rule operators
OperatorMatches when…
is / is not attribute equals (or doesn't) a value in / not in attribute is one of a list contains string attribute contains a substring > / < / between numeric or date comparison Percentage rollouts
Ship to a fraction of matched users and ramp up over time. FlagFish hashes the user key so buckets stay consistent as you increase the percentage.
// rule: pro users in EU, ramped to 40% { if: [{ plan: 'pro' }, { region: 'eu' }], serve: true, rollout: 40 }
Reorder rules by dragging in the dashboard. Because first-match wins, put your most specific rules at the top.