How to Write a Software Requirements Document Before You Hire a Developer

Send three software companies the message "we need an ERP for our business" and you will get three quotes that cannot be compared: one for a small stock system, one for a full platform, one for a guess in between. The difference is not the companies. It is that each one had to imagine what you meant. A requirements document removes the guessing, so the quotes describe the same thing and you can choose between them on substance.

You do not need to be technical to write one. You need to describe your own business clearly, which you already know better than any developer. This guide gives the sections, what goes in each, and the mistakes that make a brief unhelpful.

What a requirements document is, and what it is not

It is a description of what the software must let people do, and the conditions it must work under. It is not a design. Drawing screens too early fixes decisions that a good developer might make better, and it hides the actual need behind a picture. Describe the job; let the people you hire propose the screens.

The sections, in order

How to write the requirements themselves

Section 4 is the heart of the document. Write each requirement as one sentence naming who does what, and why if it is not obvious. This format, often called a user story, keeps the focus on the work rather than the technology.

• Vague: "The system should manage inventory." Useful: "When goods arrive, the store keeper records the quantity received against the purchase order, and stock updates immediately."
• Vague: "Good reporting." Useful: "Every Monday the owner can see last week's sales by product and by salesperson, and export it to Excel."
• Vague: "User-friendly." Useful: "A new salesperson can create a quotation without training, on a phone."

For the most important requirements, add how you will know it works. These are acceptance criteria, and they become the checklist for testing before you pay for a stage. For example: "Stock never goes below zero; if an order would make it negative, the system warns the salesperson."

Mark what matters most

Not everything is equally urgent. Mark each requirement as must have, should have or later. This is what lets a developer propose a first version that fits your budget, and it is what lets you compare quotes fairly. A company that quotes for every item, including the ones marked later, is not giving you a cheaper or dearer price; it is pricing a different project.

Where most briefs go wrong

• Copying another product's feature list. Your business does not need everything a packaged ERP does. List what your people actually do.
• Leaving out the exceptions. Returns, partial deliveries, credit customers and price overrides are where the effort is. Mention them.
• One line for integrations. "Connect to QuickBooks" can mean a nightly export or a live two-way sync. Say what moves, which way and how often.
• Forgetting the old data. Moving years of records into a new system is real work. Say what has to come across and where it is now.
• No out-of-scope list. Without one, every missing item becomes a dispute later.
• Writing it alone. Ask the people who do the work to read section 3. They will find the steps you forgot.

How to use it to compare quotes

How a quote is structured matters as much as its total. Fixed price or time and materials explains the two contract models, how much custom software costs explains what moves the number, and how to choose a software development partner covers what to check beyond the price.

We read every brief we receive, however rough, and reply with the questions we would need answered to quote it. If you would rather talk it through first, our custom software development team can turn a conversation into this document with you during a discovery call. Send us what you have.