APIs have become a critical part of the Web, especially if you're a developer. If you want to tap into some of the most useful sites out there, then an API is your best bet. But for businesses, managing a popular API can be a huge headache. For those consuming APIs, you really have very little way to monitor what's going on, and you depend on the provider to keep you informed.

But what if there was a simple service to monitor API requests and serve up good analytics? That service is Apigee, a freemium tool which puts data on API usage in your hands. Apigee was built by Sonoa Systems, a company that offers cloud services and API management for enterprises.

The API Economy

Apigee is part of what will surely become a booming sector. As APIs become a standard addition to any serious application, the need to properly monitor those APIs from both ends becomes apparent. It's an obvious usage case for businesses seeking to understand the behavior of their API.

But a real win is that Apigee will let anyone who uses an API sign up to monitor it. For all those languishing under poorly managed APIs (Are you reading this, Twitter?), Apigee will give you the opportunity to see analytics on the service. If knowledge is power, then Apigee puts power in the hands of developers.

The exact information that Apigee provides on an API includes traffic, developers using the API, response times, errors, and data volumes. It allows those managing an API to control it directly; you can actually throttle your API from the Apigee interface, responding in real time to protect an app. Developers using APIs get an opportunity to see immediately if an API is up and running, rather than relying on users to tip them off when a mashup breaks.

Another company doing something similar to this is Mashery. [Disclosure: Mashery is a ReadWriteWeb sponsor.] Mashery does API management and analytics as well, but it's not freemium and it doesn't really serve those who consume APIs as well as manage them.

The Catch

We think Apigee is awesome but there are a few caveats. In order to provide data on API activity, the service has to use a proxy. Other monitoring tools simply won't work for an API, but running it through an Apigee proxy will produce a latency.

How much latency is really the question, and each API will be able to withstand a different amount of it before users notice a lag. At this point, Apigee representatives are saying it's about 300 milliseconds, tops. So it's not a disaster, but it is impeding anything that's truly real time.

Sonoa has typically been much more focused on big enterprises looking to cash in on their APIs and services in the cloud. But Apigee is a little different. The service is free for 10,000 requests an hour. Only those making 20,000 requests or more will have to pay an annual fee.

Even with some latency issues, there are going to be product managers and developers who simply cannot live without better information about what is now a key aspect of so many Web and mobile applications. From where we sit, Apigee is an important addition to the growing Web ecosystem of APIs.