How long should a PRD be?

Three to six pages for most features. Complex projects with multiple user flows or integration requirements might stretch to eight pages. If you are over eight pages, consider splitting the work into multiple PRDs. Length is not a sign of thoroughness. It is usually a sign that the scope is too large or the document includes information that belongs elsewhere (design specs, business cases, meeting notes).

Should I write a PRD for small features?

For features that take less than a sprint, a PRD is usually overkill. A well-written ticket with a problem statement, acceptance criteria, and edge cases is sufficient. The threshold is team-specific: if two or more engineers will be working on something, or if the feature touches multiple parts of the system, a PRD is worth the investment.

Who should review the PRD before the team sees it?

At minimum, the tech lead or engineering manager. They catch feasibility issues and missing edge cases before the broader team reads it. If the feature involves design, include the lead designer. Do not send it to 10 people for review. More reviewers means more conflicting feedback and a longer cycle time.

How do I handle PRDs for features I inherited from another PM?

Start by talking to the engineers who built the current version. They know more about the constraints and history than any document will tell you. Then write a fresh PRD for the changes you are proposing, referencing the existing implementation as the baseline. Do not try to retrofit someone else's PRD. It is faster and clearer to start fresh.

What tools should I use to write PRDs?

The tool matters far less than the structure and the location. Use whatever your team already uses for documentation: Notion, Confluence, Google Docs, or even a markdown file in the repo. The key is that the PRD lives where engineers will encounter it naturally, not in a separate system they have to remember to check.

How to Write a PRD That Engineers Actually Read

TL;DR: Most PRDs collect dust in Confluence. Here's how to write product requirements documents that engineers reference daily, with structure, examples, and the mistakes that kill readership.

The PRD Nobody Reads

You spent three days on a 12-page PRD. You posted it in Slack with a request for feedback. Two engineers reacted with a thumbs-up emoji. Nobody left a comment. Two sprints later, a developer asks you a question that is answered on page 4, paragraph 3.

This is not an engineering problem. It is a writing problem.

Most PRDs fail because they are written for the wrong audience (stakeholders who want to feel informed) instead of the right audience (engineers who need to build the thing). As Marty Cagan at SVPG has argued for years, the best product teams work from shared understanding of the problem, not from thick specification documents. The best product requirements documents are not exhaustive records of every decision ever made. They are working reference documents that answer the questions a developer has at 2pm on a Wednesday when they are deep in implementation.

What a PRD Actually Needs to Do

A PRD has exactly three jobs:

Align the team on what we are building and why. Not how. The "how" belongs to engineering.
Provide enough detail to start implementation. Not to finish it. Details emerge during development.
Create a reference point for scope decisions. When someone asks "should we also handle X?", the PRD is where you look.

If your PRD is not doing all three, it is either too thin or too bloated. Most are too bloated.

The Anatomy of a PRD That Gets Used

Here is what goes in, what stays out, and why.

What goes in

Problem statement (3-5 sentences). What is the user problem? Who experiences it? How do we know it is real? This is not a business case. It is a clear articulation of the pain. Include a specific user scenario if possible.

Bad: "Users need better onboarding to improve activation rates."

Good: "New users who sign up via our marketing site abandon the setup flow at the integrations step (67% drop-off, per Amplitude). They do not understand why connecting their data source is required before they can see the dashboard. The current flow forces 4 integration steps before showing any value."

Success metrics (2-4 metrics). How will we know this worked? Use the RICE framework to validate that the expected impact justifies the effort. Be specific about the measurement window and the baseline.

Bad: "Improve onboarding completion."

Good: "Increase integration step completion from 33% to 55% within 30 days of launch. Secondary: reduce median time-to-first-dashboard from 14 minutes to 6 minutes."

Scope: what is in and what is out. This section prevents more scope creep than any other. Be explicit about what you are deliberately not building. Engineers appreciate knowing the boundaries. Use the RICE calculator to score features that are on the edge of scope: if it does not score well enough, move it to the "out of scope" list with a note.

User stories or requirements (numbered list). Use whatever format your team prefers, but number them. Numbered requirements let engineers reference specific items in code reviews, standup, and Slack. "Hey, does requirement 7 cover the edge case where..." is faster than "that thing about the error state in the second section."

Edge cases and error states. This is where most PRDs fall short. Engineers will discover these anyway. The difference is whether they discover them at 2pm when they can ask you, or at 11pm when they make a guess. Document the edge cases you know about. Add a note: "There are probably edge cases I have not considered. Flag them when you find them and we will decide together."

Open questions. Every PRD has things the PM does not know yet. List them explicitly instead of pretending you have all the answers. Mark each with a deadline: "Need answer by sprint start" vs. "Can decide during implementation."

What stays out

Implementation details. Do not prescribe database schemas, API structures, or component architecture. If you feel the urge to write "use a Redux store for this," stop. You are overstepping. Amazon's Working Backwards process takes this even further: their product documents start with the customer press release and FAQ, keeping the focus on the problem and outcome rather than technical approach. The exception: if there are genuine technical constraints (must use existing API v2, must work offline), state the constraint without dictating the solution.

Business justification essays. The PRD is not a pitch deck. Your stakeholders already approved this work. Engineers do not need three paragraphs about market dynamics to build a feature.

Full design specifications. Link to the Figma file. Do not paste 15 screenshots with annotations into the PRD. Screenshots go stale. Figma links stay current.

Meeting notes and decision history. "On January 14th, the leadership team discussed..." Nobody needs this in the PRD. If decision context matters, summarize the decision and the key trade-off in one sentence. Put the full history in a separate decision log.

PRD vs. Feature Spec vs. Product Brief

These terms get used interchangeably, but they serve different purposes:

Document	Audience	Purpose	Length
Product Brief	Leadership, stakeholders	Justify why we should invest	1-2 pages
PRD	Engineering, design, QA	Define what to build	3-6 pages
Feature Spec	Individual engineers	Detail a specific feature's behavior	1-3 pages

A product brief answers "should we do this?" A PRD answers "what exactly are we building?" A feature spec answers "how should this specific interaction work?"

The product requirements document template on IdeaPlan follows the structure outlined above. Use it as a starting point, then adapt it to your team's conventions. If you are working on technically complex features, the Technical PM Handbook covers how to bridge the gap between product and engineering documentation.

The Five Mistakes That Kill PRD Readership

1. Writing a novel instead of a reference document

If your PRD is over 8 pages, something went wrong. Either the scope is too large (split it into multiple PRDs) or you are including information that belongs elsewhere.

A practical test: can an engineer find the answer to a specific question within 30 seconds of opening the doc? If the answer requires reading paragraphs of context, restructure.

2. Burying the "what" under the "why"

Some PMs put 2 pages of background, market context, and strategic rationale before the first requirement. Engineers skip all of it. Put the problem statement and requirements up front. Move context to an appendix or link to the product brief.

3. No success metrics, or fake ones

"Improve user experience" is not a metric. "Increase NPS" is barely a metric (increase from what, to what, by when?). If you cannot define measurable success criteria, you do not understand the problem well enough to write a PRD.

4. Writing requirements in passive voice

Passive voice hides who does what. "The data should be validated" raises questions: validated by the client? The server? A background job? At what point in the flow?

Active voice forces clarity: "The server validates the email format before creating the account. If the format is invalid, the API returns a 422 with the message 'Please enter a valid email address.'"

5. Treating the PRD as finished

A PRD is not a contract. It is a living document that evolves as the team learns during implementation. The best PRDs have a "Changelog" section at the bottom. Date-stamped entries like "Feb 3: Removed requirement 8 after discovering the API does not support batch operations. Added requirement 12 as the alternative approach." This keeps the document accurate and shows that it is actively maintained, which makes engineers trust it more.

How to Get Engineers to Actually Read It

Writing a good PRD is necessary but not sufficient. You also need to present it in a way that gets engagement.

Walk through it live, once

Schedule a 30-minute kickoff meeting. Share your screen. Walk through the PRD section by section. Pause after each section and ask: "What is unclear? What is missing?" This is not a presentation. It is a working session. Engineers will ask questions you did not anticipate. Capture those questions and update the PRD in real-time or immediately after.

Make it scannable

Use headers, numbered lists, and tables. Bold key decisions and constraints. Engineers scan documents; they do not read them linearly. Every section should be independently useful.

Put it where engineers already are

If your team lives in Linear, link the PRD from the project. If they use Notion, put it in the team's Notion workspace. If they use GitHub, put it in the repo's docs folder or link it from the epic issue. As Lenny Rachitsky's survey of top PMs found, document location matters more than document format. A PRD that lives in a separate tool from the team's daily workflow will not get read. Your roadmap should reference PRDs for each major initiative so there is a clear trail from strategy to specification.

Keep it updated

This is the hardest part. When scope changes, update the PRD. When an open question gets resolved, update the PRD. When an edge case gets discovered, add it. Engineers stop reading PRDs that are out of date. The moment a developer says "the PRD says X but we decided Y," you have lost trust. Maintaining the document takes 10-15 minutes per week during active development. That investment pays for itself every time a new team member joins the project or someone needs to remember why a decision was made.

A PRD Review Checklist

Before you share the PRD with the team, run through this list:

☐ Problem statement is specific and evidence-based (not just "users want this")
☐ Success metrics have baselines, targets, and measurement windows
☐ "Out of scope" section explicitly lists what you are not building
☐ Requirements are numbered for easy reference
☐ Edge cases and error states are documented (at least the known ones)
☐ Open questions are listed with owners and deadlines
☐ No implementation details (unless genuine technical constraints)
☐ Design links are included (not pasted screenshots)
☐ Document is under 8 pages
☐ You have read it from the perspective of an engineer who has zero context

If you check all 10 boxes, you have a PRD that will get read. More importantly, you have a PRD that will get used.