How to Write a Software Requirements Document (For Non-Technical Founders)

Why two days on requirements is a bargain

The same sentence can mean two different products to client and vendor. A requirements doc's value is not ceremony — it forces both sides to surface misunderstandings before code exists. Rule of thumb from experience: one day spent on requirements saves five days of rework.

It doesn't need to be professional. Screenshots plus plain language are enough, as long as the thinking is done.

The minimal structure: five parts

Fill in these five blocks and you have a usable document:

• 1. Context & goal: why build it, for whom, and what should change after launch (this decides feature trade-offs).
• 2. User roles: who uses the system; what each role can and cannot do.
• 3. Feature list: one line each in the form "who → does what → gets what", labeled P0 / P1 / P2.
• 4. Pages & flows: reference screenshots or competitor pages + "enter here, click this, arrive there".
• 5. Acceptance criteria: each phrased as a verifiable action, e.g. "the exported report contains columns X–Z and downloads as Excel".

Techniques for non-technical writers

Can't draw prototypes? Paste screenshots: circle a feature on someone else's product and label "want this". Describe flows with if-then sentences: "if stock is zero, block checkout and show a notice". Developers translate both directly into logic.

Better verbose than vague — never write "something like WeChat" or "roughly the same". Every "roughly" becomes a rework.

The eight things first drafts forget

80% of initial requirement documents miss these — each affects the quote or timeline:

• Edge cases: what happens when payment fails, the network drops, stock goes negative?
• Permission boundaries: who can delete data? Who can see revenue figures?
• Data sources: who cleanses and enters the historical data?
• Exports and reports: which dimensions, which formats?
• Notifications: SMS, email, in-app or messenger?
• Expected concurrency: how many simultaneous users at peak?
• Languages and timezones: mandatory for international products.
• Post-launch operations: who maintains content, how often?

Let the vendor draft it — but you hold the pen

The standard flow: you describe the business, the developer structures it into a requirements doc and prototype, both sides sign off, and it becomes a contract annex. This doesn't excuse you from reading — the document defines what gets accepted, line by line.

I do this requirements pass for free: a structured doc plus an itemized quote, before any commitment exists.