{"service":"FitKit API — nutrition parsing & fitness calculators","version":"1.0.0","payment":{"protocol":"x402 (HTTP 402, pay-per-call)","network":"base","asset":"USDC","price_per_call":"$0.005","pay_to":"0xE6f3c2D5CCc727cC5d6E3308c6f8E0a220797506","how":"Call any paid endpoint; the 402 response contains payment requirements. Use an x402 client (x402-fetch, x402-axios, @x402/*) to pay automatically."},"free_endpoints":{"_note":"No signup, no key. 50 calls/day/IP, real inputs — same math as the paid routes. Omit params to get a worked example.","GET /v1/ping":"liveness","GET /v1/foods":"list of recognized foods for the meal parser","GET /v1/demo/nutrition":"?q=2 eggs and a slice of toast — kcal & macros","GET /v1/demo/tdee":"?sex=male&age=30&kg=80&cm=180&activity=moderate&goal=cut","GET /v1/demo/bodyfat":"?sex=male&waist_cm=85&neck_cm=38&height_cm=180","GET /v1/demo/zones":"?age=30&resting_hr=55","GET /v1/demo/pace":"?distance_km=10&time=47:30"},"paid_endpoints":{"POST /v1/nutrition/parse":{"body":{"text":"2 eggs and a slice of toast"},"returns":"per-item + total kcal/protein/carbs/fat, fuzzy-matched against 70 common foods with household units"},"GET /v1/tdee":{"query":"sex=male|female&age=30&kg=80&cm=180&activity=moderate&goal=cut","returns":"BMR, TDEE, target kcal, macro targets (Mifflin-St Jeor)"},"GET /v1/bodyfat":{"query":"sex=male&waist_cm=85&neck_cm=38&height_cm=180","returns":"body-fat %% (US Navy circumference method) + category"},"GET /v1/zones":{"query":"age=30&resting_hr=55","returns":"HR training zones z1-z5 (Karvonen, Tanaka max-HR)"},"GET /v1/pace":{"query":"distance_km=10&time=47:30","returns":"pace per km/mile, speed, Riegel race predictions for 5k/10k/half/marathon"}},"pricing":{"subscription":{"starter":"$9/mo — 10,000 calls","pro":"$29/mo — 100,000 calls","signup":"https://smeltworks.com/fitkit/"},"per_call":"$0.005 via x402 (USDC on Base, no signup)"},"intended_users":"Habit/fitness apps and AI agents needing deterministic nutrition & training math without an LLM call."}