Key-Based Authentication

Another class of APIs requires the client to authenticate himself when accessing the service. Authentication can be done via several techniques. In this paragraph, we’ll use the simplest one: access key. An access key is a generated string containing characters and digits and associated to a user.

Of course, authentication-based APIs often also have rate limits.

There is no universal standard regarding access keys. Each service is free to use its own custom format. The client must provide its access key when accessing the API, ...