There are a lot of different levels of rigor you can aim for when writing a spec. But at its most simple, a spec simply captures what you want the product to d

There are a lot of different levels of rigor you can aim for when writing a spec. But at its most simple, a spec simply captures what you want the product to do in enough detail that you can later focus on implementing. The "big decisions" are already made. It can be as simple as the classic napkin sketch, a few notes on a whiteboard, or hundreds of pages of extensively-reviewed "shall" statements in binders. But start with Joel Spolsky's classic "Painless Functional Specifications" (read the whole series) and you'll be starting in a good place. https://www.joelonsoftware.com/2000/10/02/painless-functional-specifications-part-1-why-bother/ https://www.joelonsoftware.com/2000/10/02/painless-functiona...