HealthKit reference
HealthKit, mapped
241 identifiers in 12 groups · read from Apple’s documentation on 2026-10-02
Apple documents each HealthKit identifier on its own page and never as a set, so the questions you hit while building — can I sum this one, what unit does it come back in, does it exist on Android — are the ones the reference cannot answer. These 12 pages take the 241 identifiers a group at a time and answer all three, with every field joined from Apple’s own documentation rather than restated from memory.
The 12 groups
- ActivityThe 37 HealthKit Activity Types37 HealthKit activity types: 20 cumulative, 13 discrete, 2 documented in name only. Nine arrived in iOS 18.0. Which ones you sum and which you average.37 identifiers
- NutritionHealthKit Nutrition: 39 Dietary Types39 HealthKit nutrition types, all cumulative, 38 from iOS 8.0. Four macros plus water carry most apps. The micronutrient tail is your food database.39 identifiers
- Vital signsThe 16 HealthKit Vital Sign Types16 HealthKit vital sign identifiers: 12 quantity types (11 discrete, 1 Apple leaves undescribed), 4 category types, 4 verified Health Connect pairs.16 identifiers
- MobilityHealthKit Mobility: 9 Gait Metrics9 HealthKit mobility identifiers, 7 of them from iOS 14.0, all discrete, none with a verified Android counterpart. What each gait figure records.9 identifiers
- Body measurementsHealthKit Body Measurements: 7 Types7 HealthKit body measurement identifiers, all discrete quantity types, 4 with verified Health Connect mappings. Weight, BMI, body fat, lean mass, height.7 identifiers
- Lab and test results9 HealthKit Lab and Test Result Types9 HealthKit lab and test result identifiers: 6 discrete, 3 cumulative, 8 dating to iOS 8.0. Glucose, spirometry, insulin, and a fall counter.9 identifiers
- Reproductive healthHealthKit Reproductive Health Types17 HealthKit reproductive health identifiers, and 16 are category types that carry an enum case and a date range instead of a number. Two are iOS 27.0.17 identifiers
- Environment, hearing and divingHealthKit Hearing, UV and Diving Types10 HealthKit identifiers measure the world around the body: audio exposure in sound pressure units, UV, daylight, underwater depth and water temperature.10 identifiers
- Sleep, mindfulness and self-careHealthKit Sleep and Self-Care Types7 HealthKit identifiers cover sleep, mindfulness, hygiene events and alcohol. sleepAnalysis is a category type, so one night arrives as many records.7 identifiers
- CharacteristicsHealthKit Characteristic Types6 HealthKit characteristic identifiers, with no aggregation style, no unit family and no samples. They are read-once identity facts, not a time series.6 identifiers
- Exercise and fitness activitiesHealthKit's 21 Exercise Constants21 HealthKit workout activity constants for gym training. No units, no aggregation, no values, and ten are documented in a single sentence each.21 identifiers
- Workout activity types63 HealthKit Workout Sport Constants63 HealthKit sport constants across 11 of Apple's groups, 3 of them deprecated. swimBikeRun and transition arrived in iOS 16.0 for multisport workouts.63 identifiers
The rest of the reference
- Every HealthKit type identifierAll 241 identifiers in one filterable table — the whole set on one URL, across every group below.
- Every HealthKit error codeThe full HKError.Code set, what each actually means, and why a denied read never raises one at all.
- HealthKit by iOS versionWhich identifiers each iOS release introduced, from the 127 that shipped in iOS 8.0 to the 3 that arrived in iOS 27.0.
- Deprecated, beta and undocumentedWhat is actually deprecated (4 identifiers, by the deprecatedAt versions in Apple's availability data), whether anything is in beta, and what ships with no documentation.
- Category value enumsThe enum that decodes each of the 30 category types — 28 resolved, 2 honest nulls.
- Unit familiesEvery quantity type by unit family, and the 5 Apple leaves unstated.
- Metadata keysAll 67 HKMetadataKey constants in Apple's topic groups, with the value type only where Apple's own sentence states it.
- Query classesHow each HealthKit query class reads these types — sample, statistics, anchored, observer, descriptors — and where each bites.
- Health Connect record referenceThe Android side: all 42 Health Connect record classes, with Google's fields, permission strings and aggregate metrics.
Compiled by AIFitnessAPI from Apple’s published documentation, read 2026-10-02. Apple’s abstracts are quoted for identification; the grouping and the analysis are ours. The same data is downloadable as JSON and CSV from the datasets.