Edamam's Free Nutrition API is a powerful tool for healthy living
This is the only API on the market that allows you to submit any recipe content in free text and receive its calorie content within seconds.
The free version of the API service returns calories per serving for the recipe as well as diet, health and allergen tags for the recipe submitted. For example gluten-free, vegan, low-fat, etc.
The commercial version of the API takes the service one step further, providing detailed nutritional data with 36 nutrients on top of what you get from the free service, as well as advanced customer support.