As developers, we can often be somewhat disparaging about things we see as low tech, such as putting together detailed plans for what we're building! However, when we're building a complex Twilio application, creating a flowchart at the beginning of a project is invaluable when it comes to not only implementing, but also testing what we've built.

In order to properly test an application, you need to follow every branch in its application flow and check whether it behaves as expected. The best way to do this is to define your expectations upfront before you even start writing code.

A great way to do this is to draw a flowchart. A flowchart represents a flow in our application, including any decisions that need to be made—effectively creating branches—and the outcomes from these decisions.

We can either build these on paper, or use a range of great online tools. I use Draw.io (http://draw.io), but plenty of other great options are only a Google search away. I've included...