A developer I work with came across an interesting problem where he needed to test the error handling on the front-end side of a SPA without adding extra “hacks” in the APIs that were consumed by the front-end. I helped him with this task, without adding “hacks”, by using Fiddler. Setup Download yourself a copy of Fiddler. Once installed, you need to configure Fiddler to intercept and decrypt HTTPS requests (as I hope your APIs are chatting on HTTPS). To do so, go in Tools -> Options and under the HTTPS tab, check Capture HTTPS CONNECTs and Decrypt HTTPS traffic and select …from browsers only. Accept all the dialogs that come after checking all of those. You will see that…