A product requirements document (PRD) is how you hand off the what of your product so a team can build it. Done well, it removes guesswork. Done poorly, it is shelfware. Here is a founder-friendly approach.
The short answer
A good PRD states the problem, the users, the goals, and the specific features and behavior of the product, clearly enough that a builder would not have to guess. Keep it concise and tied to real user needs. The point is to remove ambiguity, not to write a novel.
A simple PRD structure
- Problem and goal. What problem this solves, for whom, and what success looks like.
- Users. Who will use it, and their key needs (from your interviews).
- Scope. What is in the first version and, explicitly, what is out (see how to scope an MVP).
- Features and behavior. Each feature: what it does, the key flow, and the rules and edge cases that matter.
- Data. The main things the product stores and how they relate.
- Non-functional needs. Anything about performance, security, or scale that matters.
- Out of scope / later. A visible list so cut items are sequenced, not lost.
What makes a PRD good
- Specific. "Users can reset their password via email" beats "user management."
- Tied to needs. Each requirement traces to a real user problem, not a whim.
- Honest about scope. The "out of scope" section is as important as what is in.
- Concise. Short enough that people actually read and update it.
Why PRDs get ignored (and the fix)
A PRD rots because it is prose, disconnected from the build, ambiguous, and tedious to keep current. Two developers read it differently, the code drifts, and within weeks it no longer matches reality (see why spec documents get ignored).
The durable fix is to make the spec executable. A product simulation captures the PRD's intent as a documented, runnable foundation, code and a data model that embody the decisions, so the requirements and the product cannot quietly drift apart.
Have a PRD, or need one? Start a project and turn it into something runnable.
Frequently asked
Do I need a long, formal PRD?
No. For an MVP, a clear, concise PRD beats a long one. The goal is to remove ambiguity, not to impress. A few well-structured pages that a builder could work from is plenty.
Why do PRDs get ignored?
Because they live in a document disconnected from the build, so they go stale the moment coding starts. The fix is to keep it tight and, ideally, capture the spec in something runnable, not just prose.