API Key
API Key
A string of characters—like a password—used to connect apps and web services together
In Simple Terms
An API key is a unique identifier string that acts as a dedicated access key for using an API—the gateway through which programs communicate with each other. You send it along with each API call to tell the system which app or project the request is coming from. It's also used to enforce usage limits—like "up to 1,000 requests per day"—and to calculate charges based on actual usage. If your key leaks, someone could use it without your knowledge, potentially leaving you with a significant bill.
Behind the Name
Application Programming Interface Key. The "Key" part means exactly that—a credential that grants access to an API. Just like you can't enter a house without the right key, any API endpoint that requires authentication won't let you through without one.
Take a Closer Look!
An API key is a string used to identify which app or project a request is coming from when accessing an API—the gateway through which programs communicate.
Think of it as a dedicated access key for using a web service.
It's a long string of random alphanumeric characters that you send along with every API call.
When the system receives it, it checks which project the request belongs to and whether it falls within the allowed usage quota, then grants access to data or functionality accordingly.
The two main roles are identifying the project or app and managing usage limits.
For example, it enforces caps like "up to 1,000 requests per day" and calculates charges based on actual usage.
It also serves as a line of defense against unauthorized access.
An API key is sensitive information that should never be shared.
If it leaks, someone could impersonate your project and misuse it—or you could end up with unexpected charges.
For that reason, never paste it directly into your source code and publish it to places like GitHub; always keep it strictly protected.