Experiments

getExperiment enrols the bound user into an A/B experiment and returns an ExperimentResult.

The ExperimentResult shape

public struct ExperimentResult: Sendable {
    public let inExperiment: Bool   // was the user enrolled?
    public let group: String        // assigned group, e.g. "control" / "treatment"
    public let params: Any?         // the variant params (or your defaultParams)
}

When the user is not enrolled, you get inExperiment: false, group: "control", and your defaultParams echoed back as params.

Enrol and branch

let client = try Client(["user_id": "u_123"])
let r = await client.getExperiment("checkout_button", defaultParams: ["color": "blue"])

if r.inExperiment, r.group == "treatment" {
    let color = (r.params as? [String: Any])?["color"] as? String
    // render the treatment
}

defaultParams is the value returned for params whenever the user isn't enrolled (or the experiment is absent). Pass nil if you don't need a fallback.

Tracking conversions

Record a conversion event so the analysis pipeline can compute lift. You already hold a bound Client from getExperiment, so call track straight on it — the unit is derived from the bound user (user_id, else anonymous_id), no id argument needed. Experiments are end-to-end Client-only:

let client = try Client(["user_id": "u_123"])
await client.track("{{SUCCESS_EVENT}}", properties: ["amount": 49])

logExposure is on the bound Client too — record an exposure explicitly at the point you present the treatment (re-evaluates and only emits when the bound user is enrolled). It is a no-op when the bound user has no unit, and a no-op in testing/offline mode:

await client.logExposure("checkout_button")