Stripe has released a preview feature that could help AI startups charge through the underlying costs of AI model usage to their customers. The feature allows startups to charge a markup percentage on token usage, allowing them to charge an automatic 30% above the cost of the tokens they pay the model maker. The billing tool tracks the API prices of these models and applies the profit-margin markup automatically. This could help companies who use their agents more effectively, making pricing and business model decisions crucial. Stripe has also introduced its own AI gateway, giving users access to multiple models, but not currently charging its own markup on this gateway.