Writing an App Requirements Document (PRD) That Developers Actually Understand

The single biggest cause of failed app projects is miscommunication between the founder and the development team. The founder has a vision in their head. The developer interprets that vision differently. What gets built does not match what the founder imagined. Frustration follows.

A Product Requirements Document (PRD) solves this problem. A PRD is a written document that defines exactly what your app will do, who it is for, and how it will work. It is the single source of truth that everyone — founder, designer, developer, tester — refers to throughout the project.

This guide explains how to write a PRD that developers can actually use, with a template you can adapt for your own app.

Why a PRD Matters

Without a PRD, developers make assumptions. When you say "the app should have user profiles," the developer makes assumptions about what information the profile contains, how users edit their profiles, whether profile photos are supported, and whether profiles are public or private. Some of those assumptions will be wrong.

A PRD prevents assumptions by writing everything down. It forces you to think through every feature in detail before development starts. It creates a shared reference that both you and the developer can refer to. And it provides a basis for estimating time and cost accurately.

What a PRD Includes

A good PRD covers the following sections:

Executive Summary

A one-page overview of your app. What problem does it solve? Who is it for? What makes it different from existing solutions? This section gives the development team context for all the detailed requirements that follow.

Write this section last, after you have completed all other sections. It should summarize the key points for executives or stakeholders who do not need to read the entire document.

User Personas

Detailed profiles of your target users. For each persona, include demographics (age, location, income, occupation), goals (what they want to accomplish using your app), pain points (what frustrates them about current solutions), technical proficiency (how comfortable are they with technology?), and usage context (when and where will they use your app?).

User personas help the development team make design decisions that serve real users. When developers know that their primary user is a busy Lagos professional who uses the app during commute, they make different design choices than if the user is a student with lots of free time.

User Stories

User stories describe features from the user's perspective. They follow the format: As a [type of user], I want to [action] so that [benefit].

Examples: As a customer, I want to search for products by name so that I can find what I need quickly. As a customer, I want to save items to a wishlist so that I can purchase them later. As an admin, I want to view order history so that I can process returns.

User stories are valuable because they focus on the user's goal rather than the technical implementation. They tell developers what to build while leaving room for creative solutions.

Feature List

A comprehensive list of every feature in your app, organized by priority. Use the MoSCoW method:

Must-have features are essential for the launch version. Without these, the app does not deliver value. Should-have features are important but not critical. They can be included if time and budget allow. Could-have features are nice additions that wait for future versions. Will-not-have features are explicitly excluded from this version.

Be ruthless with the Must-have list. Every feature you add increases development time and cost. Launch with the smallest set of features that delivers real value.

User Flows

Step-by-step descriptions of how users accomplish key tasks. For each flow, list every screen the user visits and every action they take.

Example user flow for "Purchase a product": User opens app → User browses home screen → User taps product category → User scrolls product list → User taps product → User views product details → User taps "Add to Cart" → User views cart → User taps "Checkout" → User enters delivery address → User selects payment method → User confirms order → User sees confirmation screen → User receives confirmation email.

User flows help developers understand the complete journey before they start coding individual screens.

Wireframes or Mockups

Visual references showing the layout and design of each screen. Wireframes can be simple sketches or created using tools like Figma. They do not need to be polished at this stage, but they help developers visualize what you want.

Technical Requirements

Any technical constraints or preferences. This includes platform choice (iOS, Android, or both), third-party integrations needed (payment gateways, mapping APIs, SMS providers), hosting and infrastructure preferences, security requirements (encryption, authentication), and performance benchmarks.

Success Metrics

How will you measure whether your app is successful? Define specific, measurable metrics such as daily active users, conversion rate, average session duration, retention rate at 30 days, and user ratings.

Success metrics help the development team prioritize features that directly impact your goals.

PRD Template

Here is a simple template you can use:

1. Executive Summary
2. Problem Statement
3. Target Audience (User Personas)
4. User Stories
5. Feature List (Must-have, Should-have, Could-have, Won't-have)
6. User Flows
7. Screen List with descriptions
8. Design References (wireframes, mockups, inspiration)
9. Technical Requirements
10. Third-Party Integrations
11. Success Metrics
12. Timeline and Milestones
13. Open Questions

Common PRD Mistakes

Writing too much detail about implementation. Describe what the app should do, not how developers should build it. Let developers determine the best technical approach.

Not including the "why" behind features. When developers understand why a feature exists, they make better implementation decisions. Include the user need or business goal for each feature.

Treating the PRD as a static document. The PRD should evolve as you learn more during design and development. Changes should be documented and agreed upon, not made informally in conversation.

Writing the PRD alone. Involve potential users, stakeholders, and even your developer in the PRD process. Different perspectives catch issues you might miss.

Being too vague. "The app should have good performance" is not a requirement. "The home screen should load in under 2 seconds on a 4G connection" is a requirement.

How Joetech Approaches Requirements

At Joetech, we help clients develop their PRD as part of our discovery phase. We provide a structured template, guide you through each section, and ask the questions that help you think through your requirements thoroughly. By the time development starts, we have a shared document that both sides have reviewed and approved.

Contact us to discuss your app idea and learn about our discovery and requirements process.

Next article: UI Design vs UX Design in Apps: Why Both Matter and Neither Is Optional