  Getting acquainted with a large codebase can be a daunting task for software
developers, both new and seasoned. The description of a codebase and its
development should be the purpose of its documentation. However, software
documentation, if it exists at all, is usually textual and accompanied only by
simple static diagrams. It is also time-consuming to maintain manually. Even an
API reference, which can be generated automatically from the codebase itself,
has many drawbacks. It is limited to what it can extract from the codebase, is
cumbersome to navigate, and fails to capture the interwoven nature of code. We
explore an alternative approach centered around a node-link diagram
representing the structure of a codebase. The diagram is interactive and
filterable, providing details on demand. It is designed for automation, relying
on static analysis of the codebase, and thus produces results quickly and
offers a viable alternative to missing or outdated documentation. To evaluate
this approach, we implemented a prototype named Helveg that is able to analyze
and visualize C# code. Testing with five professional programmers provided
feedback on the approach's benefits and challenges, which we discuss in detail.
