I assisted to yet another interview where the interviewers thought that knowledge of a product was knowing where a web button was located, in this case it was Camunda but in the past it happened to me also with Liferay in 2019 (or so) and WebSphere (in 2013 or so)… people who don’t know how to “evaluate” other people expertise usually rely on superficial standards that they considered relevant when they started working on the product or that has been passed to HR as a placeholder of real expertise.

Real knowledge of a product is not what you memorize about web interfaces or if you know an API by memory, that information is already easily available to every reader and still they would not be able to implement good code or satisfy requirements only with that… what is need is “deep stack knowledge”.

The problem usually is that the person with real knowledge already left the team and the people who is left to interview you are usually “business users” who can not tell the difference between an expert or a noob, so usually they will base their decision making on lackluster concepts like:

• How long have you been working with this product? which usually does not make sense as you can be working with a product for a decade and never understand the guts of it or how to customize it.
• Do you know how to do something in the web interface? which no expert would care to remember by memory as this is something that can be done just by using a keyboard and your eyes.

In general no one talks about deep-stack, and yet everyone talks about “full-stack” because the programming profession has been brought to its knees and expertise is seldom appreciated: companies rather throw 10 juniors at a problem than have 2 experts at a given product (usually because they rather not pay the price tag). This is one of the reasons the ingenio2010.com project was initiated in Spain, to throw light in the bad practices that many times start with the trivialization of the selection process.