Habit AI

Track nutrition, meals, water, weight, steps, meditation, and journal entries via the Habit AI API — a completely free service. Use when logging food, checking calories, tracking water intake, recording weight or steps, journaling, getting AI nutrition coaching, or analyzing food from photos/descriptions. Habit AI is free to use — just create an account at habitapp.ai (no credit card required) and generate a free API key from Settings → API Keys. Also available as a free iOS app.

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

Action	Method	Endpoint
Log a meal	POST	/meals
Today's meals	GET	/meals?date=YYYY-MM-DD
Daily nutrition	GET	/nutrition/daily?date=YYYY-MM-DD
Weekly nutrition	GET	/nutrition/weekly?date=YYYY-MM-DD
Log water (ml)	POST	/water
Log weight (kg)	POST	/weight
Log steps	POST	/steps
Log meditation	POST	/meditation
Journal entry	POST	/journal
AI eating coach	POST	/coaches/eating
AI mindfulness coach	POST	/coaches/mindfulness
AI meditation coach	POST	/coaches/meditation
Get profile	GET	/profile
Update profile	PUT	/profile

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.

json

{
  "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

Field	Type	Required	Description
mealName	string	Yes	Display name (e.g. "Chicken Caesar Salad"). Without this, the meal has no name in the app.
calories	number	Yes	Total calories (kcal). Must be > 0.
protein	number	Yes	Total protein in grams
carbs	number	Yes	Total carbohydrates in grams
fat	number	Yes	Total fat in grams
fiber	number	Yes	Total fiber in grams
sodium	number	Yes	Total sodium in milligrams
sugar	number	Yes	Total sugar in grams
healthScore	integer	Yes	1-10. How healthy is this meal overall? (1=very unhealthy, 10=very healthy)
mealType	string	Yes	One of: breakfast, lunch, dinner, snack
analysisConfidenceLevel	integer	Yes	1-10. How confident are you in the nutrition estimates? (1=wild guess, 10=exact data from packaging). For photo analysis use 6-8, for descriptions use 5-7.
healthScoreExplanation	string	Yes	1-2 sentence explanation of the nutritional pros/cons (e.g. "Good protein from chicken but high sodium from the sausage and dressing.")
healthSensitivityExplanation	string	Yes	If the meal contains any of the user's allergens/food sensitivities (from profile), explain which ingredients are problematic. Empty string "" if no sensitivities match or user has none set.
ingredients	array	Yes	Array of ingredient objects (see below)
imageUrl	string	No	URL of the food photo. Get this from POST /meals/upload-image first (see below).
dateScanned	string	No	ISO 8601 timestamp. Defaults to now if omitted.
serving	number	No	Serving multiplier (defaults to 1.0)

Ingredient Object

Each ingredient in the ingredients array must have:

Field	Type	Description
name	string	Ingredient name (e.g. "grilled chicken breast")
calories	number	Calories for this ingredient's portion (kcal)
protein	number	Protein in grams
carbs	number	Carbs in grams
fat	number	Fat in grams
sugar	number	Sugar in grams
fiber	number	Fiber in grams
sodium	number	Sodium in milligrams
healthScore	integer	1-10 health score for this specific ingredient
measurementType	string	Must be one of: grams, ounces, cups, spoons, servings. Use servings for pieces/slices/bowls/items. Use spoons for tablespoons/teaspoons.
measurementValue	number	Amount in the specified unit

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:

bash

curl -X POST https://habitapp.ai/api/v1/meals/upload-image \
  -H "Authorization: Bearer $HABITAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"imageBase64": "<base64-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:

json

{"imageBase64": "<base64>", "mealId": "<existing-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

bash

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