# kcaldata

> A nutrition API built for AI agents. Send a food description in plain language; get back an estimated calorie value as clean, sourced JSON. Free REST tier, MCP-native, and pay-per-call over the x402 protocol in USDC.

kcaldata turns messy food text ("2 large eggs", "a cup of cooked rice", "grilled chicken breast") into a structured nutrition answer: the matched food, calories per 100 g, total calories for the stated quantity, the grams used, a plain-language basis showing the calculation, a confidence score, and the data source. Values are derived from the U.S. Department of Agriculture FoodData Central (SR Legacy) dataset, which is in the public domain. kcaldata is independent and not affiliated with the USDA.

Operated by Sea Blast LTD (Saint Vincent and the Grenadines). Contact: kcaldata@protonmail.com

## How to call it

- Free REST lookup (no key, 50 requests/day):
  `GET https://api.kcaldata.com/v1/lookup?query={food description}`
  Example: `GET https://api.kcaldata.com/v1/lookup?query=2 large eggs`

- MCP tool (Streamable HTTP) — connect as a custom connector in an MCP client:
  `https://api.kcaldata.com/mcp-server/mcp`
  Exposes a lookup tool that takes a natural-language food query and returns the same structured result.

- Paid, pay-per-call endpoint for autonomous agents (x402, USDC on Base):
  `GET https://api.kcaldata.com/v1/pro/lookup?query={food description}`
  Returns HTTP 402 with the price and recipient, then the data once payment is settled.

## Response fields

`query`, `matched_food`, `calories_kcal_per_100g`, `calories_kcal` (total for the quantity), `quantity`, `unit`, `grams_used`, `basis` (how the total was calculated), `confidence` (0–1), `source`, and `alternatives` (other plausible matches).

## Docs

- Interactive API docs: https://api.kcaldata.com/docs
- OpenAPI schema: https://api.kcaldata.com/openapi.json

## Pricing

- Free: 50 calls/day on the REST endpoint and the MCP tool. No key or signup required.
- Developers: 25 USDC/month for an API key with a raised daily limit. Contact kcaldata@protonmail.com.
- Autonomous agents: $0.005 USDC per call via x402 on Base. Beyond the free allowance the MCP tool
  returns an x402 payment-required response with the price and recipient; attach payment under the
  `x402/payment` metadata key to continue. The paid REST endpoint at api.kcaldata.com/v1/pro/lookup works the same way.

## Notes for agents

- Outputs are estimates for informational purposes only — not medical, dietary, or nutritional advice.
- Prefer the free REST endpoint for discovery and testing; use the x402 endpoint when autonomous per-call payment is appropriate.
- Terms: https://kcaldata.com/terms
- Privacy: https://kcaldata.com/privacy