What is the difference between SDK and API?

SDK refers to the software development toolkit, which is a collection of various auxiliary tools provided for professional program developers to develop specific software. Users are generally required to have a deeper understanding and research on these tools.

API is an application programming interface and a pre-packaged function library, which can be called by end users or programmers (maybe non-professionals, such as web designers) through simple methods. Users don't need to care about the internal working principle of API functions.

Let's make a popular analogy: for example, if you want to assemble a model of transformers, SDK is equivalent to various parts of transformers, assembly tools and detailed assembly instructions. You must know the relevant knowledge of model assembly, understand all kinds of technical terms in the manual, and have strong hands-on ability to finally assemble transformers of various shapes, and even make unique shapes that are not in the manual according to your own understanding and creativity. API is equivalent to an assembled transformer, which can be used together with it, or it can be a semi-finished product close to assembly. It only needs simple operation, which is very convenient, and there is no need to worry about assembly failure. However, if you want to change the shape or add something personalized, it will be a bit difficult.