Authentication

Every request to the NutrientAPI requires a valid API key sent as a Bearer token in the Authorization header. There are no query-parameter or cookie-based authentication methods.

Getting Your API Key

Sign up at nutrientapi.com to receive an API key. Keys are available on all plans, including the free tier. Once you have your key, you can start making requests immediately.

Making Authenticated Requests

Include your API key in the Authorization header using the Bearer scheme:

Authorization: Bearer YOUR_API_KEY

Every request must also set Content-Type: application/json since the API only accepts JSON request bodies.

cURL

curl -X POST https://api.nutrientapi.com/v1/analyze \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "title": "Greek Salad",
    "ingredients": [
      "2 cups chopped romaine lettuce",
      "1/2 cup crumbled feta cheese",
      "1/4 cup kalamata olives"
    ],
    "servings": 1
  }'

Python

import requests
import os

response = requests.post(
    "https://api.nutrientapi.com/v1/analyze",
    headers={
        "Authorization": f"Bearer {os.environ['NUTRIENT_API_KEY']}",
        "Content-Type": "application/json",
    },
    json={
        "title": "Greek Salad",
        "ingredients": [
            "2 cups chopped romaine lettuce",
            "1/2 cup crumbled feta cheese",
            "1/4 cup kalamata olives",
        ],
        "servings": 1,
    },
)

data = response.json()
print(data["total_nutrients"]["calories"])

JavaScript (Node.js)

const response = await fetch("https://api.nutrientapi.com/v1/analyze", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.NUTRIENT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    title: "Greek Salad",
    ingredients: [
      "2 cups chopped romaine lettuce",
      "1/2 cup crumbled feta cheese",
      "1/4 cup kalamata olives",
    ],
    servings: 1,
  }),
});

const data = await response.json();
console.log(data.total_nutrients.calories);

Ruby

require "net/http"
require "json"

uri = URI("https://api.nutrientapi.com/v1/analyze")
request = Net::HTTP::Post.new(uri)
request["Authorization"] = "Bearer #{ENV['NUTRIENT_API_KEY']}"
request["Content-Type"] = "application/json"
request.body = {
  title: "Greek Salad",
  ingredients: [
    "2 cups chopped romaine lettuce",
    "1/2 cup crumbled feta cheese",
    "1/4 cup kalamata olives",
  ],
  servings: 1,
}.to_json

response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |http|
  http.request(request)
}

data = JSON.parse(response.body)
puts data["total_nutrients"]["calories"]

Authentication Errors

If authentication fails, you will receive one of these HTTP responses:

Status Code	Meaning	What to Do
401 Unauthorized	Missing or malformed Authorization header	Check that the header is present and uses the Bearer scheme
403 Forbidden	API key is invalid, expired, or revoked	Verify the key in your dashboard; rotate if necessary
429 Too Many Requests	Rate limit exceeded for your plan	Back off and retry; consider upgrading your plan for higher limits

All error responses follow a consistent JSON format:

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or missing API key"
  }
}

Best Practices

• Use environment variables to store your API key. Never hard-code it.
• Rotate keys periodically from your dashboard, especially if team members leave.
• Use a server-side proxy if your frontend needs nutrition data. The proxy makes authenticated requests on behalf of the client, keeping your key off the network.
• Cache responses aggressively. All plans allow full caching with no attribution required. The same recipe input will always produce the same result, so there is no reason to re-request identical analyses.