OpenAPIPricing is an open research project on API pricing. We read the public pricing pages of 150 APIs across 19 categories, record the plans, free tiers and billing models, and publish every figure with its source link and the date we verified it. We also email providers to get the latest pricing. Each API gets a pricing guide, and the biggest names get side-by-side comparisons. The goal is simple: pricing anyone can check without a sales call.