As we face the realities of climate change, it is becoming increasingly important to consider the environmental impact of the software we develop. APIs are no exception. According to Slashdata, nearly 90% of developers use APIs. In this talk, we will share our experiences and insights into building climate-friendly, sustainable APIs through the use of green software practices. You may have seen eco-mode options in washing machines and modern cars. It is time to implement eco-mode in APIs and give developers more power to help reduce energy consumption. By the end of the talk, you will have a clear understanding of design principles for architecting and building climate-friendly APIs through shifting sustainability left and considering sustainability a non-functional requirement.