What Is an API Key, and How Are They Used?

When programmers build an application, it often includes an application programming interface (API). An API is a tool that simplifies the implementation of a more complex process by hiding non-essential aspects.

That’s a bit abstract, so let’s use a real-world example. Let’s say you’re an ecommerce platform that accepts online payments. You could build a whole template from scratch, complete with 128-bit security. Or you could do the same thing and license a secure sales form for your site. That form is an API.

Another good example is a shipping form or an email signup form. These forms need to link to databases, which isn’t terribly complex for programmers. But if you’re building your own website, it could be a bit intimidating. By using an API, even a novice can build a site with functional forms.

Here’s What We’ll Cover:

What Is an API Key?

API Keys vs. Authentication Tokens

When to Use an API Key

Key Takeaways

What Is an API Key?

An application programming interface key (API key) is a unique piece of code that’s sent from one application to another on a network. This is an essential part of digital security. It prevents unauthorized programs from accessing a given function.

The purpose of an API key is to ensure that a given interface is only being used the way it’s intended. A good example of an API key would be the ones used by major streaming services. Netflix hosts their movies on a cloud server, which is connected to the web. How do they stop people from mass-downloading them?

They use an API key. When a device attempts to access their service, Netflix to make sure that the correct app is doing the accessing. So you can watch Netflix movies in the Netflix app, but you can’t open them in Windows Media Player.

Keep in mind that API keys are only part of a broader authentication scheme. They identify only the program that is accessing a particular API. They don’t provide individual user authentication. For that, you need an authentication token.

API Keys vs. Authentication Tokens

So, when should you use an API key, and when should you use an authentication token? API keys provide visibility to the application attempting to access a given API server. If the key is valid, the server will allow the application to connect. The server will simply ignore invalid API requests.

Another useful feature of API keys is that they can limit access to a given operating system or IP address range. Let’s say you have one version of your online sales form for European users, and another for Americans. An API key would let the sales platform know which version of the form to call up.

That said, API keys are not entirely secure. By their very nature, developers need to make them available to partners and clients. This makes the key available to a large number of people, any of whom might steal it.

Further complicating matters, the only way to revoke unauthorized access would be to revoke the entire key. This could cut off access to authorized users, at least until programmers manually generate and deliver a new key.

Authentication tokens are unique digital tokens that go beyond basic authentication. They identify individual users. These can provide far more control than a simple API key. For example, a token can be associated with a particular role, so users will have the right kind of access.

For example, let’s say you use cloud accounting software. You might want some people to only be able to enter expenses, while others could view the company’s entire financial record. By assigning individual tokens to users, the system ensures that everyone can access the right features.

When to Use an API Key

The fundamental purpose of an API key is to limit API functions with an application restriction. This can be useful for a number of reasons. First, you might want to limit access rights to authorized programs, as we’ve already discussed.

Second, application information can be useful for debugging purposes. Even if you don’t want to limit access, it can be useful to know what browser someone was using when your API crashed. Similarly, API key data can allow you to identify usage patterns for analytics purposes.

Finally, an API key can be used to limit the number of calls to your API. This can be helpful if you have limited API server resources.

Key Takeaways

API keys don’t provide a perfect security solution. But as part of a broader authentication scheme, they provide an added layer of security. Such a scheme should include individual identity tokens. They also provide project identification for compatibility and analytics purposes.

Enjoyed this article? Read more on our resource hub.

---

RELATED ARTICLES