How the primitives connect
Every A/B test in Fleack starts with traffic your app already sends to your backend. Fleack captures that traffic, classifies what it sees, and lets you declare parameters worth testing. From there, tests run automatically against the users you choose, and the results engine tells you when you have a winner.The five primitives
Endpoints are the API URL patterns your app calls. Fleack observes them and classifies each one — only endpoints with consistent, non-user-specific responses are eligible for testing. Learn more → Levers are individual parameters inside an endpoint’s response that you’ve declared as testable — identified by a JSON path likedata.gems_reward or ads.interstitial_frequency. Learn more →
Tests bind a lever to a set of variant values and a target audience. Each test runs with sticky per-user assignment so every user consistently sees the same variant. Learn more →
Segments define which users are eligible for a test, using built-in attributes like platform and country, plus profile attributes drawn from your own user-data endpoints. Learn more →
Results are computed by the Bayesian engine from exposure records — giving you a win probability per variant so you know exactly when to promote a winner. Learn more →
Explore each primitive
Endpoints
How Fleack classifies your API traffic and which endpoints are testable.
Levers
Declaring individual response parameters as testable targets.
Tests
Building variant experiments and managing their lifecycle.
Segments
Targeting specific audiences with built-in and profile attributes.
Results
Bayesian win probability and when to promote a winning variant.
Quickstart
Go from zero to a live test in under five minutes.