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FFMI API

Compute FFMI metrics with optional formatted output and unit support for metric or imperial inputs.

Endpoint

  • GET /api/v1/ffmi
  • POST /api/v1/ffmi/post

Parameters

Name Type Required In Description
sex string (male,female) Yes Query/Body Biological sex.
height number Yes Query/Body Height (cm metric, in imperial).
weight number Yes Query/Body Weight (kg metric, lb imperial).
body_fat number Yes Query/Body Body-fat percentage.
unit string (metric,imperial) No Query/Body Input mode. Default metric.
format string (yes,no) No Query/Body Output formatting toggle.
lang string No Query Response language (en,es,de,fr,pt,ja,hi,ar).

Why Use This Endpoint

  • Add lean-mass quality scoring to body composition products.
  • Compare raw vs normalized FFMI for fair benchmarking.
  • Enable athlete-segment insights with sex-specific ranges.

Get Started

Request Example

curl -X GET "https://api.hefitapi.com/api/v1/ffmi?sex=male&height=178&weight=82&body_fat=16&unit=metric&format=yes&lang=en" \
  -H "X-API-Key: YOUR_API_KEY"

curl -X POST "https://api.hefitapi.com/api/v1/ffmi/post?lang=en" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"sex":"male","height":178,"weight":82,"body_fat":16,"unit":"metric","format":"yes"}'

Response Example

Info

The response example below is for demonstration purposes only. Make a live request to this endpoint to receive the full, real-time, and potentially richer JSON structure.

{
  "FFMI": "19.38 kg/m2",
  "Normalized FFMI": "19.51 kg/m2",
  "Fat-free mass": "68.88 kg",
  "Total body fat": "13.12 kg",
  "Sex": "male",
  "Unit": "metric",
  "ffmi_value": 19.38,
  "normalized_ffmi_value": 19.51,
  "fat_free_mass_kg": 68.88,
  "total_body_fat_kg": 13.12,
  "ffmi_band": "standard",
  "ffmi_band_label": "Standard",
  "risk_signal": "Lean mass status is within expected range.",
  "action_plan": ["Progress overload gradually"],
  "monitoring_plan": "Track every mesocycle.",
  "language": "en",
  "_enterprise": {
    "client": "Acme Health",
    "plan": "pro",
    "request_id": "de948be84a08433f",
    "quota": 120,
    "usage_tracking": true
  },
  "_api_metadata_": {
    "endpoint_name": "ffmi",
    "response_language": "en"
  }
}

Commercial Positioning

Perfect for advanced physique analytics, strength coaching products, and athlete monitoring stacks.

Note

format=no returns non-string numeric presentation for top-level FFMI display fields.