I absolutely don’t understand this conception.
If we are talking about special token for developers, why we should throttle them? Why its name not a “token”?
Why we use id if we already have user_id parameter?
If it’s not about developers, why it calls api_DEV_key.
Every time in every chapter in System Design course I see this parameter and can’t understand it.
Sometimes a server throttles a user if they act like a spam bot. Now to avoid this we use the api_dev_key.
The course is taking an abstract approach towards system design hence it’s being called the api_DEV_key.
An api_key/api_dev_key can also be used to specify how much throttling they may receive. Like an admin user may get more quota than a regular user.
The api_dev_key is used to authenticate a user before it gets access to the API. This link shows how an API key is used.