Why Skipping a Functional Requirements Document Can Doom Your Project

WHY - Why You Need a Functional Requirements Document

Without a proper document, teams suffer from high communication overhead, mismatched expectations, costly rework, and endless code deletions when requirements change.

WHERE - Where to Store the Document

The document must stay up‑to‑date and be shared with all stakeholders. Real‑time cloud collaboration tools (Google Docs, Office Online, Shimo Docs, etc.) are far more efficient than sending files via QQ, email, or other ad‑hoc methods.

WHAT - What a Functional Requirements Document Should Contain

A good document describes every feature in detail, includes project background, detailed feature descriptions, out‑of‑scope items, usage scenarios, flowcharts, role definitions, and prototype sketches.

Typical sections:

Project background

Detailed feature point description

Out‑of‑scope feature explanation

Use‑case scenarios (with vivid description)

Flowcharts (Visio, OmniGraffle, ProcessOn, etc.)

Personnel role "instantiation" examples

Reference to product prototype designs

HOW - How to Ensure Document Quality

Keep the document live: update it immediately when requirements change and require every team member to consult it before coding. Reject any verbal, QQ, or email request that is not reflected in the document, ensuring developers follow the documented specifications.