DX, developer experience begins with a well-designed API. But that’s not all that matters. What should we care about when creating the product with the API to give the best DX? Or what should we be aware of when choosing an API product to get not only features of the product but also some nice experience when working with it? While creating our platform at Intento, we deal with dozens of AI API. Using these interfaces as examples we will analyze 8 API characteristics such as reliability, onboarding, ease of maintenance and more. We will see which of the API providers create more headaches than provide functionality. The same approach can be used to decide which payment service to connect to the site. Or while building team communication between backend and frontend developers creating one service. Say, for a frontend developer it will be easier to explain to colleagues what exactly complicates her or his life as a backend API user. Besides we will dive into a marvelous new world of modern AI services.