What is a product requirements document (PRD)?

A product requirements document (PRD) is an artifact that explains the requirements, functionality, and features of the product you want to build. It serves as a single source of truth for the designers and developers involved in the project. 

It communicates to the development team what they’re building, who it’s for, and how it’ll deliver value to end users and your business. 

PRDs are often associated with waterfall development environments where product definition, design, and delivery happen sequentially. They are especially ideal for businesses building highly complex products or those in highly regulated industries requiring extensive documentation.

PRDs are also used in Agile development—an approach that allows more adaptability and flexibility in project planning. 

Typically, in Agile development, the PRD follows a similar format, detailing the product's features, functionality, and development timeline, but it’s not a static document. In an agile framework, the PRD is a continuously evolving document where user stories and requirements are added and prioritized throughout the product development process. 

Building a successful product or feature requires the effective collaboration of all the project stakeholders. A PRD acts as a crucial reference point for all the teams involved in product development. 

It keeps all the stakeholders in sync, moving in the same direction (towards a common goal), which ensures that you deliver what your customers like, on time. A PRD is also a starting point from which other team members plan their courses and create necessary artifacts. This means that you can derive several other documents from the PRD. 

For instance:

• The engineering team can create a TRD (technical requirements document) highlighting the product's system requirements and specifications.

• Business analysts can derive a functional requirements document (FRD) describing what should happen when users interact with the product, including wireframes to show the product design.

• UX designers can create a user interface requirements document describing how the product should look and feel.

The components of a PRD may vary depending on several factors, including the product you’re building, the teams involved, and the type of business you’re creating it for, especially in overly regulated industries. However, any standard PRD will feature a combination of the following components:

Project overview

This is an overview of the product you’re building and serves as an introduction to what the PRD will cover. This section lists the stakeholders of the project and some general information about the product, such as its purpose and the expected release date. 

Product objectives

This section outlines the context of the product while aligning it with the larger vision of your company. Here, explain why you’re developing the product and what you hope to accomplish with the product's release. This helps keep the project stakeholders focused on a common goal.

Keep these simple. You don't need to write a long, exhaustive list of objectives. Simply outline the essential features necessary to foster good customer experiences and address their needs effectively.

Customer research & design notes

The secret sauce for successful product development is knowing the customer and correctly identifying their needs. In this section, outline the target audience for the product and their pain points. Include customer or market research to help the development teams build products that match the target audience. 

In addition to the research, this section should also include any design elements, including possibly a working prototype, hexadecimal colors, pixel dimensions, and any unique interactions necessary to carry out the planned design.

Product features

This is arguably the most crucial part of your PRD. Here, you list all the product features, capabilities, and use cases you’ll deliver in the release. In Agile development, this section may also include UX design notes and user stories.

In addition, explain the purpose of each feature and the problem it seeks to address. As a best practice, when outlining what the developers need to build, be precise so that they can determine how best to implement it.

Negative scope

It's important to highlight what you’ll not include in the release to keep the development team focused on what matters most. By detailing what's out of scope, you can save the development teams from going down dead ends that only take up time and additional costs to the project. 

Also, consider outlining elements that are out of scope but that you might consider in future product enhancements.

Assumptions, constraints & dependencies

It's also essential that your PRD lists the following aspects of the project development:

• Assumptions:includes anything that you expect to be in place but isn't guaranteed

• Constraints:highlights the potential obstacles that may impede the development process

• Dependencies:anything that the release is dependent on for success, for instance, a dog walking app that depends on Google Maps to add direction

Release criteria

Your PRD should also include release criteria. This section describes the prerequisites the product needs to meet to be deemed ready for public release. Generally, the release criteria cover the following aspects:

• Functionality: outlining the minimum functionalities required to release the product

• Usability:describing the scope of user testing 

• Reliability: clarifying how reliable your product should be for it to be ready for release

• Performance: highlighting the performance baseline of the product, such as memory consumption and loading time

• Supportability: determining whether standard user systems can effectively support your product

Timeline

A good PRD must also have a timeline. In this section of the PRD, detail the deadline for product completion. If you have various iterations or components of a product, consider setting multiple release dates for each to help team members plan their work. 

In addition, although the timeline should be flexible enough to allow a change in requirements, it should also protect you against project creep by limiting the number of features the development teams can add without significantly altering the targeted release date.

System requirements

This is the more technical piece of the document. The system requirements section should detail what needs to be in place mechanically. It may include any system or environmental requirements (i.e., this product should run on iOS 15.5 or later).

Success metrics

Bearing in mind your product objectives, this is where you define the metrics that’ll help you measure whether the project is successful or otherwise. Specify the crucial indicators of success and outline how you’ll track them. 

Consider creating a hypothesis about the desired impact of the product and then set quantifiable goals. For instance, you can use the following performance indicators to measure the success of your product:

• Percentage of users who interact with the product

• How users navigate workflows

• How frequently users interact with your product

• Duration of time users take interacting with your product, among others

The goal is to have something measurable you can check on to clearly mark as successful or not.

Pros of a PRD

The main benefit of a PRD is that it’s a single source of truth that helps the project stakeholders—the development team, along with support, sales, and marketing—to effectively collaborate and deliver an excellent product experience that delights customers and drives growth in a business. 

Here are the main benefits of a PRD:

• Outlines high-level objectives for the product

• Helps avoid assumptions about product goals and scope of work

• Documents desired functionality and user experience

• Details timelines

• Provides necessary context for cross-functional teams

Drawbacks of a PRD

The challenges of a product requirements document include the following:

• Can limit creativity if seemingly handed down "from above"

• Becomes irrelevant if stakeholders do not collaborate

• Requires expertise to write effectively

• Insufficient or incorrect insight into customer behavior and needs may lead to poor products

A PRD should be created ideally at the beginning of the product development process, as soon as you determine user need for a product. It helps define the project's scope and ensures all stakeholders have a shared understanding of what’s required to create a successful product.

You can also update your PRD in the course project as you identify new requirements or when you alter the project scope.

A market requirements document (MRD) outlines the market opportunity or the customer demand, i.e., the customer needs that a product seeks to address. On the other hand, a PRD details how the product will be built.

A PRD is applied throughout the development process. You can use it to guide the design and development process, communicate with team members, and ensure the product addresses the target audience's needs.