Spoonacular is the dominant food-data API — many fitness, smart-kitchen, and diet apps use it. It aggregates multiple sources (own recipe library, partner blogger recipes, branded food nutrition databases) into a unified API. Most useful features: ingredient-based recipe suggestion ("I have eggs, potatoes, onions in the fridge, what can I make"), dish nutrition calculation (input ingredients+quantities, returns calories and macros), dish image recognition (upload photo to identify), filtering (gluten-free, vegan, ketogenic, etc.). Chinese cuisine coverage is weak (mostly Western and East Asian); for Chinese-market recipe apps, use domestic platforms like Xiachufang. Free tier 150/day; commercial $29-249/month.