So, the University of Illinois Urbana-Champaign¹ has an API for course information. It exists as a part of something called the “Course Information Suite”, or CIS for short. As far as I can tell, the documentation is out of date, or at the very least fails to accurately describe how to utilize the API. This post details what I’ve deciphered about the API and how you can use it.

Table of Contents

• The Problem(s)
• The Solution
  • GenEds
  • The XML Schema
• Conclusion

The Problem(s)

The gist of the issue seems to be that, at some point, they decided to consolidate the API but failed to update the documentation alongside it. The CIS documentation is split up into three sections²:

• CIS API Documentation
• Data Explorer App
• Link Dispatcher App³

Each of these describe endpoints attached to the courses.illinois.edu URL.

• CIS API Documentation = /cisapi
• Data Explorer App = /cisapp/explorer
• Link Dispatcher App = /cisapp/dispatcher

Now, the key error in the documentation is this:

…the /cisapi endpoint does not work.

Play with it as much as you like, you will consistently find yourself with an HTML 404 page response. So… how do you get course data, then? The obvious answer is “the Data Explorer App, duh”… which is essentially the response I received when I got in touch with the University’s head software engineer—a tad discouraging, to say the least⁴.

You see, the Data Explorer App documentation is a lot sparser that the CIS API documentation. It doesn’t have the detailed description of endpoints (/schedule/year, schedule/courses, etc) that the CIS API documentation does. It semed that, through the aforementioned consolidation, we no longer had access to a number of useful endpoints.

However, if you’ve done your due diligence, you’ll notice that by searching Github you can find how people have used the /cisapp/explorer endpoints. And, if you’re like me, you’ll come to a sinking realization:

…all the /cisapi/schedule endpoints work if you make them match the /cisapp/explorer format.

The Solution

Once I figured out that this was the main error in the documentation, I threw together a tool that can take any example URL from the documentation of the /cisapi/schedule endpoints, and make it a working /cisapp/explorer/schedule endpoint. And, due to the flexibility of the /schedule/courses endpoint, the need for functioning /gened, /term, /subjects endpoints(which don’t work with the Data Explorer) was negated. You can access the tool below:

The moral of the story, then, is that if you want to build a project that uses the UIUC CIS API, you can simply reference the /cisapi documentation to your heart’s content, and use the above tool to get the corresponding /cisapp/explorer URL when you need it. That way, you get all the detail out of the /cisapi documentation, and all the actually-working functionality of the /cisapp/explorer endpoints.

GenEds

…and if you’d like to use the schedule/courses endpoint to find courses that match a particular gened requirement, you can use the following codes⁵:

The XML Schema

Another issue with the documentation is that the link to the XML schema is broken. Thankfully, I was able to gain access to it during my correspondence with the head software engineer. I’ve hosted it on Github, and a link to download it can be found found under the tool I mentioned earlier, at mirth.cc/cisurls-web/cisapi.xsd.

Conclusion

This was by no means a comprehensive explanation of the UIUC CIS API. Frankly, the only place you could get that would be from the minds behind it, and I doubt they have the time or energy to exhaustively elaborate on how this stuff works. At the very least, I hope this post helps clear some of the fog around the API and make it easier to understand and utilize for tinkering students. All of this is stuff I’ve figured out by getting my hands dirty, and it is entirely possible that I’ve written here some misconception or mistake. Please take everything with a grain of salt, and if you have any questions, feel free to reach out to me by email.