Habit AI

Track health and nutrition through the Habit AI REST API.

Setup (100% Free)

Habit AI is a completely free service — no subscription, no credit card, no usage limits.

1. Create a free account at https://habitapp.ai (or download the free iOS app)
2. Go to Settings → API Keys → Create Key (free, up to 5 keys)
3. Store key in environment: export HABITAI_API_KEY="hab_..."

All requests use:

• Base URL: https://habitapp.ai/api/v1
• Auth header: Authorization: Bearer $HABITAI_API_KEY
• Content-Type: application/json

Quick Reference

For full endpoint details (request/response schemas, all parameters), see references/api.md.

Logging Meals — The Right Way

⚠️ CRITICAL: Use the AI model to analyze food, then POST /meals with the EXACT structure below

Do NOT call /analyze/food-image or /analyze/meal-description — instead, use your own vision/language capabilities to analyze the food, then construct the exact JSON structure below and POST it to /meals.

Step 0: Check user profile for allergens/diet

Before analyzing, call GET /profile to check foodSensitivities and diet fields. Factor these into:

• healthScore — lower the score if the meal contains ingredients the user is sensitive to
• healthScoreExplanation — mention the general nutritional pros/cons
• healthSensitivityExplanation — if the meal contains any of the user's allergens/sensitivities, explain which ingredients are problematic and why. Leave empty string if no sensitivities match.

Step 1: Analyze the food yourself

For photos: Look at the image and identify each ingredient, estimate portions, and calculate nutrition using USDA data.

For descriptions: Parse the meal description and calculate nutrition the same way.

Step 2: POST /meals with the EXACT structure

Every field matters. iOS reads from nutritionalSummary (nested object) — if it's missing, meals show as 0 calories.

{
  "mealName": "Grilled Chicken Salad with Ranch",
  "calories": 520,
  "protein": 42,
  "carbs": 18,
  "fat": 32,
  "fiber": 4,
  "sodium": 890,
  "sugar": 6,
  "healthScore": 7,
  "healthScoreExplanation": "Lean protein from grilled chicken and fiber from greens, but ranch dressing adds significant fat and sodium.",
  "mealType": "lunch",
  "analysisConfidenceLevel": 8,
  "ingredients": [
    {
      "name": "grilled chicken breast",
      "calories": 280,
      "protein": 35,
      "carbs": 0,
      "fat": 14,
      "sugar": 0,
      "fiber": 0,
      "sodium": 400,
      "healthScore": 8,
      "measurementType": "grams",
      "measurementValue": 200
    },
    {
      "name": "mixed salad greens",
      "calories": 20,
      "protein": 2,
      "carbs": 4,
      "fat": 0,
      "sugar": 1,
      "fiber": 2,
      "sodium": 30,
      "healthScore": 9,
      "measurementType": "cups",
      "measurementValue": 2
    },
    {
      "name": "ranch dressing",
      "calories": 220,
      "protein": 5,
      "carbs": 14,
      "fat": 18,
      "sugar": 5,
      "fiber": 2,
      "sodium": 460,
      "healthScore": 3,
      "measurementType": "spoons",
      "measurementValue": 3
    }
  ]
}

Field Reference

Ingredient Object

Each ingredient in the ingredients array must have:

Important Rules

1. All nutrition values must be numbers, not strings. "calories": 520 not "calories": "520"
2. Ingredient calories should sum to the total calories (approximately — within 5%)
3. mealName is mandatory — without it, the meal is invisible on iOS
4. healthScore is 1-10 integer — use your judgment (fast food = 2-4, home-cooked balanced = 6-8, raw salad = 9-10)
5. analysisConfidenceLevel is 1-10 integer — be honest about uncertainty
6. Sodium is in milligrams, everything else is in grams (except calories in kcal)

Uploading a meal photo (thumbnail)

If you have a food photo, upload it first to get a URL:

curl -X POST https://habitapp.ai/api/v1/meals/upload-image \
  -H "Authorization: Bearer $HABITAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"imageBase64": "\x3Cbase64-encoded-image>"}'

Returns: {"success": true, "imageUrl": "https://firebasestorage.googleapis.com/..."}

Then pass imageUrl in your POST /meals call. You can also attach to an existing meal:

{"imageBase64": "\x3Cbase64>", "mealId": "\x3Cexisting-meal-id>"}

Full flow with photo:

1. POST /meals/upload-image with base64 photo → get imageUrl
2. POST /meals with nutrition data + imageUrl

Other Workflows

Check remaining calories

1. GET /nutrition/daily for today's totals
2. GET /profile for calorie goal
3. Subtract: caloriesGoal - totalCalories

Quick water log

curl -X POST https://habitapp.ai/api/v1/water \
  -H "Authorization: Bearer $HABITAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"amount": 500}'

Amount is in milliliters. 1 cup ≈ 237ml, 1 glass ≈ 250ml.

Notes

• Dates default to today if omitted (uses user's timezone from profile)
• Water amount is in milliliters
• Weight is in kilograms (1 lb ≈ 0.4536 kg)
• Steps auto-calculate calories burned if profile has height/weight/gender
• Max 5 API keys per account