How do I write a software requirements document for a development agency?

Why the Document Matters Before You Engage a Dev Agency

Agencies estimate and price work based on what you hand them. A vague brief produces a vague quote and, eventually, scope creep. A clear SRD aligns both sides on what success looks like before a single line of code is written.

Core Sections of a Solid SRD

1. Project Overview

One or two paragraphs: the problem you're solving, who has the problem, and why software is the right solution. Avoid jargon. This grounds every decision that follows.

2. Goals and Success Metrics

State measurable outcomes — for example, reduce manual invoice processing time by 50% or onboard 1,000 users in the first 90 days. Metrics help the agency make the right trade-offs during build.

3. Users and Roles

List each type of user (e.g., admin, end user, external partner) and what they need to do. A simple table works well:

4. Functional Requirements

These are the specific things the software must do. Write them as user stories or numbered statements:

• User story format: As a [role], I want to [action] so that [outcome].
• Statement format: The system shall allow users to reset their password via email.

Prioritize using MoSCoW labels: Must Have, Should Have, Could Have, Won't Have (for now). This tells the agency what to build in phase one versus later.

5. Non-Functional Requirements

Cover performance, security, compliance, scalability, and accessibility expectations. Examples: page load under 2 seconds, GDPR-compliant data handling, supports 10,000 concurrent users. These often drive architectural decisions and cost.

6. Integrations and Dependencies

List any third-party services, APIs, or existing systems the new software must connect to — payment gateways, CRMs, ERPs, or internal databases. Agencies need this to assess complexity.

7. Constraints and Assumptions

Be explicit about budget bands, target platforms (web, iOS, Android), preferred tech stack (if any), and regulatory requirements. Also list assumptions you're making so the agency can flag where they disagree.

8. Wireframes or User Flows (Optional but Valuable)

Even rough sketches or a clickable Figma prototype dramatically reduce misinterpretation. You don't need polished design — just enough to show how screens connect.

Practical Tips

• Keep the SRD version-controlled. Decisions change; the document should reflect them.
• Share it before a formal kick-off and ask the agency to flag gaps or contradictions.
• Don't over-specify implementation details unless you have a strong technical reason — let the agency solve how while you own what and why.

How CodeNicely Approaches This

CodeNicely runs a structured discovery session with new clients to co-write or refine the requirements document before scoping begins. If you have a rough brief, that's a fine starting point — the goal is to leave discovery with a shared, signed-off spec so estimates are accurate and milestones are meaningful.