When you’re commissioning a software agency to build something for you, e.g. your version 1 MVP, there’s a thing that you can write called a “specification”.
This is a document that contains a detailed description of what the software should do.
However, people hate writing specifications, people hate reading specification, and even the people who like writing them aren’t usually very good at it. In short, finding a good specification is “white tiger rare”.
However, if you want a fixed price project, this CANNOT BE DONE without a GOOD specification.
The reason for this is that in order to estimate the project properly, the supplier has to know what they are building. The only way to get agreement on what they going to build for you is to have someone write it down in a specification.
I feel like I need to stress this – any fixed price quote from a software agency is only valid if it is accompanied by a GOOD specification.
There’s another topic here about “agile” pricing and development with software agencies, but that’s a port for another day.