Cisco provides two other excellent, at the time of writing free, methods of practice API interaction with various Cisco gears. Both of the tools require Cisco connection online login. They are both really good, especially for the price point (they are free!). It is hard for me to imagine that these online tools will remain free for long, it is my belief that at some point, these tools need to be charging money for usage or be rolled into a bigger initiative that required some fee. however we can take advantage of them while they are available at no extra charge.

The first tool is DevNet (https://developer.cisco.com/), which includes guided learning tracks, complete documentation, and sandbox remote labs, among other benefits. Some of the labs are always on, while some you need to reserve and availability depends on usage. In my experience with DevNet, some of the documentations and links were outdated, but they can be easily retrieved for the most updated version. In a rapidly changing field such as software development, this is somewhat expected. DevNet is certainly a tool that you should take full advantage of regardless of whether you have a locally run VIRL host or not:

Another online lab option for Cisco is Cisco dCloud. You can think of dCloud as running VIRL in other people's server without having to manage or pay for those resources. It seems that Cisco is treating dCloud as both a standalone product as well as an extension to VIRL. For example, the case when you are unable to run more than a few IOX-XR or NX-OS instances locally, you can use dCloud to extend your local lab. It is a relatively new tool, but it is definitely worth a look: