Bad specifications are the number-one cause of software project overruns. This step-by-step guide helps non-technical founders write specs that developers can actually build from.
In our experience, 70 % of software project delays trace back to a single root cause: the client and the developer had different mental models of what was being built. A good specification closes that gap before the first line of code is written.
Start with user stories, not features
Instead of "the system should have a dashboard", write: "As a sales manager, I want to see total revenue for the current month on the home screen so that I can check performance without running a report." User stories force you to name who is doing what and why — three pieces of information that unlock every design decision downstream.
The five sections every spec needs
- 1. Problem statement: one paragraph explaining the pain you are solving and for whom.
- 2. User roles: list every type of person who will use the system and their core goal.
- 3. Core features: 5–10 user stories that cover 80 % of daily usage. Resist listing everything.
- 4. Out of scope: explicitly state what the first version will NOT do. This prevents scope creep.
- 5. Constraints: budget ceiling, launch date, existing systems the software must integrate with, compliance requirements.
Wireframes beat words
A hand-drawn sketch of a key screen communicates more than three paragraphs of text. Tools like Figma Community (free), Excalidraw, or even a photograph of a whiteboard sketch help enormously. You do not need design skills — rough boxes with labels are enough.
The one question that reveals unclear specs
After writing your spec, ask: "If my developer built exactly what I described and nothing more, would the result solve my problem?" If the answer is no, there is something important you have not written down yet.
"Measure twice, cut once. Write twice, code once."
