Glucose API

Operation

public func predict(
    _ request: PredictGlucoseRequest
) async throws -> GlucosePrediction

Request and defaults

public struct PredictGlucoseRequest: Hashable, Sendable {
    public init(
        userProfile: GlucosePredictionProfile,
        foods: [FoodSelection],
        startTime: Date,
        cgmData: [CgmReading]? = nil,
        consumedFoods: [ConsumedHistoricalFood]? = nil,
        endUserID: PartnerUserID? = nil,
        timezone: TimeZone? = nil
    )
}

JanuaryClient.glucose sends the client's timezone and ignores the request's endUserID and timezone.

Profile

public struct GlucosePredictionProfile: Codable, Hashable, Sendable {
    public init(
        age: Double,
        sex: Sex,
        height: Height,
        weight: Weight,
        activityLevel: ActivityLevel? = nil,
        healthConditions: [MedicalCondition]? = nil
    )
}

The legacy gender:height:weight: initializer interprets raw height as inches and raw weight as pounds. Prefer the typed initializer.

Optional history

CgmReading requires an ISO 8601 timestamp string and a numeric value. ConsumedHistoricalFood requires timestamp, FoodID, and ConsumedHistoricalServing. Invalid timestamp strings fail locally with .validation.

Response

GlucosePrediction exposes:

• prediction: [GlucosePredictionPoint];

• impact: GlucoseImpact?;

• chart: GlucoseChart;

• the older aliases curve, scoring, minimum, and maximum.

GlucosePredictionPoint has minutes after startTime and the predicted value in mg/dL. GlucoseChart has optional min and max: suggested y-axis bounds in mg/dL, not the curve's lowest and highest points. GlucoseImpact is a RawRepresentable struct that can carry values added later; compare against .lowImpact, .mediumImpact, and .highImpact without assuming they're the only ones. See Read the result.

Errors

Predict checks that age is a whole number and that history timestamps are ISO 8601 before sending. It maps 400 to .validation, 401 to .authentication, 403 to .authorization, 429 to .rateLimited, and 504 to .timeout; other API errors map to JanuaryError by status.