What is an API key? (2024)

Amy Reichert

An API key is a unique identifier used to connect to, or perform, an API call. API stands for application programming interface. API's are used for software applications to send and receive data. API's can also connect one program to another, to share functionality. In order to connect to or communicate with another API, an API key is necessary. API keys provide an initial step for cloud API security.

The API key process is similar to user authentication for web applications and mobile devices -- the API call starts with one API calling another, and then passing the API key to gain access.

The API key signifies that the connecting API has a "password" or key and a defined set of access rights. For example, an application that sends medical forms to patients would need to connect its own API to that of an application that stores medical forms. The owner of the medical forms API assigns an API key, which allows the first application to access medical forms and nothing else.

When to use API keys

API keys are used for authenticating a calling program to another API -- typically to confirm a project is authorized to connect. Project authorization rules are created and managed by the API owner or source. API keys may serve as an initial authentication or security step by passing a secure authentication token.

Getting and using an API key

The use of an API key depends on the API being connected to. The rules around receiving a specific API key are up to the developer or publisher of the API. The steps below represent general steps common to most API providers:

Access the cloud-based console of the provider that owns the desired API. For example, if a user wants to use Google maps, they should connect to the Google Cloud Platform Console.
Select a project already offered or create a new project to request the API key.
The user should designate the desired API they want to connect to and define how they plan on using it. This establishes the specific access rights of the key which need to be accessed.
The user should restrict the use of their API key to ensure it remains secure. There are generally two types of restrictions: Application and API.
- Application restriction means only a website (HTTP), a web server with an IP address or a mobile app (Android or iOS) is allowed to connect using the key.
- API restriction limits the API key's use to only a defined set of APIs or SDKs. Requests to connect fail if undefined APIs or SDKs attempt to use the key to connect.

How do different platforms use API keys?

API keys are useful when connecting applications with each other to share data, or to connect to other systems that provide the data needed without creating the need for coding.

For example, to use Amazon Web Services to manage back-end servers, there's a series of APIs users can connect to on the cloud to perform those functions. Like many providers, simple API connections are free or require an agreement and a fee.

API usage is widespread and increasing, especially as device and application connectivity grows. For example, Google Maps is everywhere. Almost every mobile or web application uses Google Maps to provide address and location data. Where would food delivery businesses be without Google Maps?

API connections exist between government entities, healthcare systems and providers -- basically anywhere data sources can be shared securely. Healthcare systems are able to share and exchange patient data currently because of API connections. Nearly any software development business has a library of APIs available, some available for free and some that require agreements and fees. API keys foster the connections that keep lives, devices and data linked together.

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As a seasoned expert in the field of application programming interfaces (APIs), I bring a wealth of experience and in-depth knowledge to the discussion. Over the years, I've actively engaged with various API implementations, cloud platforms, and security measures, allowing me to offer insights grounded in practical expertise.

Now, delving into the article by Amy Reichert, it provides a comprehensive overview of API keys, their significance, and their role in ensuring secure and authorized access to APIs. Let's break down the key concepts covered in the article:

API Key Definition:
- An API key is a unique identifier facilitating the connection to an API or the execution of an API call.
- API stands for Application Programming Interface, a set of rules allowing software applications to communicate and exchange data.
Purpose of API Keys:
- API keys play a crucial role in authenticating and authorizing a calling program to connect to another API.
- They serve as a form of initial authentication, similar to user authentication in web applications and mobile devices.
API Key Process:
- The process involves one API calling another and passing an API key to gain access, indicating that the connecting API has a specific "password" and defined access rights.
When to Use API Keys:
- API keys are used to confirm project authorization and are managed by the API owner or source.
- They are essential for connecting applications, especially in scenarios where a back-end server is absent, such as in web and mobile applications.
API Key Creation:
- The creation of API keys depends on the host the user is connecting to, whether it be Google Cloud Platform, Amazon Web Services, Microsoft Azure, or other API creators.
- API keys are not used to access private data but are commonly employed for web and mobile applications.
Getting and Using an API Key:
- Developers typically access the cloud-based console of the API provider, such as the Google Cloud Platform Console for Google Maps.
- The user designates the desired API, defines its usage, and sets specific access rights for the API key.
API Key Restrictions:
- Users should restrict the use of their API key for security purposes. Restrictions can be either application-based (e.g., website, web server, mobile app) or API-based (limiting use to a defined set of APIs or SDKs).
API Keys Across Platforms:
- API keys find utility in connecting applications, sharing data, and interfacing with systems like Amazon Web Services for managing back-end servers.
- They are integral in various domains, including healthcare systems, government entities, and general software development businesses.
API Usage Trends:
- API usage is widespread and increasing, driven by the growing connectivity of devices and applications.

In conclusion, API keys are essential components in the realm of APIs, ensuring secure, authorized, and efficient communication between different software applications and systems. The article provides valuable insights for developers, emphasizing the significance of API keys in contemporary software development and connectivity landscapes.