A business requirements document (BRD) says what the business needs from a piece of work and why, in money-and-outcomes terms rather than technical ones. On client work it is usually the document the contract points at, which makes it what you open when someone disputes what was included.
What distinguishes a BRD from a PRD
A BRD is written in the language of the business: the objective, the commercial rationale, the stakeholders, the success criteria, the budget and timeline envelope. A PRD is written in the language of the product: what it must do, for which users, in which situations. The BRD says "reduce support contacts about billing by a third this quarter"; the PRD says what the billing screen must therefore let someone do.
What to include
On an agency or consultancy engagement, the exclusions section is the one that earns its keep. Everything else is upside; exclusions are what stop a fixed fee eroding.
- Business objective
- The outcome the organisation is buying, and why now.
- Stakeholders
- Who has a say, who signs off, and who is merely informed. Ambiguity here is the source of most late-stage scope arguments.
- Scope and exclusions
- What the engagement covers, and explicitly what it does not. The second list is the one people skip and later need.
- Success criteria
- How the business will judge whether it worked.
- Assumptions
- What has to be true for the plan to hold - client availability, third-party access, data quality.
- Constraints
- Budget, deadline, regulatory or platform limits.
Why it matters most on client work
An in-house team can absorb an ambiguous requirement; a fixed-fee engagement cannot. When the client remembers a feature being in scope and the delivery team remembers it being out, the BRD is what settles it - if it exists, if it was tagged at sign-off, and if the exclusions were written down. All three fail together surprisingly often.
Frequently asked questions
Do we need both a BRD and a PRD?
On internal work, often one document covers both. On client work the separation is usually worth keeping, because the BRD is a commercial agreement and the PRD is a working document that changes.
Who signs a BRD?
Whoever holds the budget on the client side, and the delivery lead on yours. If nobody signs it, it is a proposal rather than an agreement.
How Spectr helps
Keep a requirements doc that is still true next month
Versioned BRDs and PRDs that stay current, and can generate a spec sheet directly
Related terms
Spend less of the week on documents
Spectr drafts the spec, the requirement document and the stories from your meetings. You review and approve.
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