PRD vs BRD vs MRD: Which Document Do You Actually Need?

Three documents. One feature.

Somewhere in the process of building software, product teams created three different documents for describing what they're building: the Market Requirements Document, the Business Requirements Document, and the Product Requirements Document. Then they argued about which one is required, who writes it, and what goes in it.

Here's what each document is actually for — and the honest answer to which ones you need.

The MRD: Market Requirements Document

The MRD answers: Is there a market for this?

It's the most upstream document in the chain. An MRD describes the market opportunity — who has the problem, how many of them there are, what they're currently doing about it, and what a solution in this space would need to do to win.

Who writes it: Product management, sometimes with input from product marketing or research.

Who reads it: Executives making investment decisions, product leadership deciding whether to fund a new area, product marketing aligning on positioning.

What's in it:

• Market segmentation and target customer profile
• Problem definition and evidence of market demand
• Competitive landscape
• Market sizing (TAM/SAM)
• High-level requirements from the market's perspective — not features, but outcomes customers need to achieve

When you need one: When you're evaluating a genuinely new product area or a significant strategic pivot. When leadership needs to decide whether to invest resources in a new direction before committing to anything.

When you can skip it: For features within an existing, well-understood product line. You don't need an MRD every time you ship a new filter option.

The BRD: Business Requirements Document

The BRD answers: What does the business need from this?

This is the enterprise software world's document. In large organisations — especially those with IT departments, compliance requirements, and procurement processes — the BRD captures the business-level requirements that a system must meet before it can be used.

Who writes it: Business analysts, project managers, or product managers in enterprise/IT contexts.

Who reads it: IT teams evaluating systems, procurement, compliance, project sponsors, sometimes the software vendor's implementation team.

What's in it:

• Business objectives the system must support
• Functional requirements from the business's perspective
• Compliance and regulatory requirements
• Integration requirements with existing systems
• Non-functional requirements (SLAs, security standards)
• Assumptions and constraints

When you need one: In enterprise B2B contexts, particularly when implementing third-party software or building systems for regulated industries. When there's a formal procurement or approval process. When an IT department will be owning and operating the system you're building.

When you can skip it: Almost always, for consumer products and most SaaS. For a product team building their own software, the BRD format adds bureaucratic overhead without adding clarity.

The PRD: Product Requirements Document

The PRD answers: What are we building and why?

This is the document product managers own. The product requirements document bridges market and business context with what engineering needs to build. It describes the problem, the user, the proposed solution, and the acceptance criteria that define when the solution is done.

Who writes it: Product manager.

Who reads it: Engineering (primary audience), design, QA, support, product marketing, stakeholders reviewing the plan.

What's in it:

• Problem statement
• Target user and their context
• Goals and non-goals
• User stories with acceptance criteria
• Functional requirements
• Non-functional requirements (performance, accessibility, security)
• Edge cases
• Analytics events to instrument
• Open questions

When you need one: For any feature with non-trivial engineering effort, cross-team dependencies, or meaningful user impact. For anything that involves trade-offs an engineer needs context to make.

When you can skip it: For bug fixes, small iterative improvements where the change is self-evident, or very small teams where the PM and engineer are in constant communication anyway.

How They Relate to Each Other

The three documents are sequential, not parallel:

MRD → answers whether to invest at all → informs BRD/PRD → the PRD describes what to build within that investment

In practice, most product teams collapse the MRD into the PRD. The "problem statement" and "market context" sections of a well-written PRD cover what an MRD would say, just in less detail.

The BRD lives in a different lane entirely — it's an enterprise/IT document, not a product-team document. Modern SaaS product teams don't typically write BRDs. They write PRDs.

The Honest Answer for Most Product Teams

If you're on a SaaS product team, the answer is: write PRDs, skip the rest unless you have a specific reason to need them.

The MRD becomes relevant when you're making a genuinely new strategic bet and need an explicit decision point with leadership. In that case, a 2–3 page strategic brief (which most people will call an MRD even if it doesn't follow any formal template) is useful.

The BRD becomes relevant if you're selling into enterprise, where procurement and IT departments need formal documentation of system requirements. If your customers are asking for it, write it.

For everything else: one well-written PRD, scoped to the specific feature, reviewed with engineering before sprint planning, is more useful than three documents that overlap and contradict each other.

PRD Format: The Sections That Matter Most

If you've decided you need a product requirements document, here's the prd format that works:

1. 1Problem statement — one paragraph, from the user's perspective
2. 2Target user — specific segment, not "all users"
3. 3Goals — what success looks like at 30/90 days
4. 4Non-goals — what you're explicitly not building
5. 5User stories — with Given/When/Then acceptance criteria
6. 6Requirements — functional and non-functional, in plain language
7. 7Edge cases — the scenarios that break the happy path
8. 8Analytics — specific events to instrument
9. 9Open questions — what you don't know yet

The format matters less than the content. A PRD that clearly states the problem and has complete acceptance criteria in a Google Doc is more useful than a perfectly formatted one that leaves out the edge cases.

Use our free PRD Template as a starting point, or try PMRead to generate a PRD directly from your customer evidence.