Functional Requirements

Functional Requirements Specification (FRS): {{PROJECT_NAME}}

Project: {{PROJECT_NAME}} Version: {{VERSION}} Date: {{DATE}} Author: {{AUTHOR}} Status: Draft | In Review | Approved Reviewers: {{REVIEWERS}}

Document History

Version	Date	Author	Changes
0.1	{{DATE}}	{{AUTHOR}}	Initial draft

1. System Overview

System Name: {{SYSTEM_NAME}} System Purpose: {{PURPOSE_2_3_SENTENCES}}

System Context Diagram:

graph TB
    subgraph "{{SYSTEM_NAME}}"
        UI[Web / Mobile UI]
        API[Backend API]
        DB[(Database)]
    end
    U1[{{USER_TYPE_1}}] -->|Uses| UI
    U2[{{USER_TYPE_2}}] -->|Uses| UI
    API -->|Reads/Writes| DB
    API -->|Integrates| EXT1[{{EXTERNAL_SERVICE_1}}]
    API -->|Integrates| EXT2[{{EXTERNAL_SERVICE_2}}]
    ADM[Admin] -->|Manages| UI

2. Actors & Personas

Actor ID	Actor Name	Type	Description	Access Level
ACT-01	{{ACTOR_NAME}}	Human / System	{{DESCRIPTION}}	{{ROLE/PERMISSIONS}}
ACT-02	End User	Human	{{PERSONA_DESCRIPTION}}	Authenticated user
ACT-03	Administrator	Human	Manages system configuration and users	Admin
ACT-04	{{EXTERNAL_SYSTEM}}	System	External service integrated via API	System

Persona Detail

Persona: {{PERSONA_NAME}}

Role: {{JOB_TITLE}}
Goal: {{PRIMARY_GOAL_USING_SYSTEM}}
Pain Points: {{CURRENT_FRUSTRATIONS}}
Tech Savviness: Low / Medium / High
Frequency of Use: Daily / Weekly / Monthly

3. Functional Requirements

3.1 Module: {{MODULE_1_NAME}}

Module Overview

FR-001: {{FEATURE_NAME}}

Attribute	Value
Module	{{MODULE_1_NAME}}
Priority	Must Have
Trace	BR-{{XXX}}
UI Reference	`[Figma link or mockup filename]`

Description: {{FEATURE_DESCRIPTION_IN_BUSINESS_LANGUAGE}}

Acceptance Criteria:

Given {{PRECONDITION}}, when {{USER_ACTION}}, then {{EXPECTED_RESULT}}
Given {{PRECONDITION}}, when {{USER_ACTION}}, then {{EXPECTED_RESULT}}
Given invalid input, when {{USER_ACTION}}, then {{ERROR_HANDLING}}

Data Requirements:

Input: {{INPUT_DATA_FIELDS_AND_TYPES}}
Output: {{OUTPUT_DATA}}
Validation: {{VALIDATION_RULES}}

Business Rules:

RUL-{{XX}}: {{APPLICABLE_BUSINESS_RULE}}

Dependencies: FR-{{XXX}}, DEP-{{XX}}

FR-002: {{FEATURE_NAME}}

Attribute	Value
Module	{{MODULE_1_NAME}}
Priority	Must Have
Trace	BR-{{XXX}}
UI Reference

Description: {{FEATURE_DESCRIPTION}}

Acceptance Criteria:

Given {{PRECONDITION}}, when {{USER_ACTION}}, then {{EXPECTED_RESULT}}
Given {{PRECONDITION}}, when {{USER_ACTION}}, then {{EXPECTED_RESULT}}

Data Requirements:

Input: {{INPUT}}
Output: {{OUTPUT}}
Validation: {{VALIDATION}}

Business Rules: {{APPLICABLE_RULES}}

Dependencies: {{DEPENDENCIES}}

3.2 Module: {{MODULE_2_NAME}}

Module Overview

FR-010: {{FEATURE_NAME}}

Attribute	Value
Module	{{MODULE_2_NAME}}
Priority	Must Have
Trace	BR-{{XXX}}
UI Reference

Description: {{FEATURE_DESCRIPTION}}

Acceptance Criteria:

Given {{PRECONDITION}}, when {{USER_ACTION}}, then {{EXPECTED_RESULT}}
Given {{PRECONDITION}}, when {{USER_ACTION}}, then {{EXPECTED_RESULT}}

Data Requirements:

Input: {{INPUT}}
Output: {{OUTPUT}}
Validation: {{VALIDATION}}

Business Rules: {{APPLICABLE_RULES}}

Dependencies: {{DEPENDENCIES}}

3.3 Module: Authentication & Authorization

FR-020: User Registration

Attribute	Value
Priority	Must Have
Trace	BR-{{XXX}}

Description: Users can create a new account using email and password.

Acceptance Criteria:

Given a valid email and password (≥8 chars, 1 uppercase, 1 number), when user submits registration form, then account is created and confirmation email is sent
Given an already-registered email, when user tries to register, then system shows "Email already in use" error
Given password does not meet complexity rules, when user submits, then inline validation error shown before submit

Data Requirements:

Input: email (unique), password, {{ADDITIONAL_FIELDS}}
Output: user record, confirmation token
Validation: email format, password complexity, duplicate check

Attribute	Value
Priority	Must Have
Trace	BR-{{XXX}}

Description: Authenticated users can log in with email and password.

Acceptance Criteria:

Given valid credentials, when user submits login form, then user is authenticated and redirected to dashboard
Given invalid credentials, when user submits, then generic error "Invalid email or password" is shown (no enumeration)
Given 5 consecutive failed attempts, when user tries again, then account is temporarily locked for 15 minutes
Given an authenticated session, when user is idle for 30 minutes, then session expires and user is redirected to login

3.4 Module: {{MODULE_N_NAME}}

FR-030: {{FEATURE_NAME}}

4. Use Case Diagrams

4.1 {{MODULE_1_NAME}} Use Cases

graph LR
    A1(({{ACTOR_1}})) --> UC1[FR-001: {{FEATURE}}]
    A1 --> UC2[FR-002: {{FEATURE}}]
    A2(({{ACTOR_2}})) --> UC3[FR-010: {{FEATURE}}]
    A2 --> UC4[FR-011: {{FEATURE}}]
    A3((Admin)) --> UC5[FR-020: {{FEATURE}}]
    A3 --> UC6[FR-021: {{FEATURE}}]

4.2 System-Level Use Case Overview

graph LR
    subgraph "{{SYSTEM_NAME}}"
        UC1[{{MODULE_1}} Functions]
        UC2[{{MODULE_2}} Functions]
        UC3[Auth Functions]
    end
    ACT1(({{ACTOR_1}})) --> UC1
    ACT1 --> UC3
    ACT2(({{ACTOR_2}})) --> UC2
    ACT2 --> UC3
    ACT3((Admin)) --> UC1
    ACT3 --> UC2
    ACT3 --> UC3

5. System Behavior Specifications

5.1 Error Handling

All user-facing errors must display a human-readable message (no stack traces)
All errors must be logged with correlation ID, timestamp, user ID (if authenticated), and action
Validation errors shown inline, adjacent to the invalid field
System errors show generic message + contact info; full detail logged server-side only

5.2 Data Persistence

All user-submitted data must be persisted within {{X}} seconds
Optimistic UI updates must be rolled back if server confirmation fails
All mutations (create/update/delete) must be audited with user ID and timestamp

5.3 Session & State

Session timeout: {{X}} minutes of inactivity
Concurrent session behavior: {{ALLOW/BLOCK/NOTIFY}}
Browser refresh: application state must be restored from server

5.4 Notifications

Email notifications: {{WHICH_EVENTS_TRIGGER_EMAILS}}
In-app notifications: {{WHICH_EVENTS_TRIGGER_IN_APP}}
Push notifications: {{IF_APPLICABLE}}
Unsubscribe mechanism required for all marketing emails (GDPR)

5.5 Accessibility

WCAG 2.1 Level AA compliance required
Keyboard navigation for all interactive elements
Screen reader compatibility (ARIA labels)
Color contrast ratio ≥ 4.5:1

6. Requirements Summary Table

ID	Feature Name	Module	Priority	Status	Trace
FR-001	{{FEATURE}}	{{MODULE}}	Must Have	Draft	BR-001
FR-002
FR-010
FR-020	User Registration	Auth	Must Have	Draft	BR-xxx
FR-021	User Login	Auth	Must Have	Draft	BR-xxx

Requirements Count:

Must Have: {{COUNT}}
Should Have: {{COUNT}}
Could Have: {{COUNT}}
Won't Have (this release): {{COUNT}}

7. Traceability to Business Requirements

FR ID	Feature Name	Business Requirement (BR ID)	Business Objective (BO ID)
FR-001	{{FEATURE}}	BR-{{XXX}}	BO-{{XX}}
FR-002

Full traceability matrix: [requirements-traceability-matrix.md](requirements-traceability-matrix.md)

Approval

Role	Name	Date	Signature
Author
Reviewer
Business Analyst
Tech Lead
Product Owner
AI Director (John)
Client Representative

Revision #3
Created 2026-02-24 15:16:24 UTC by John
Updated 2026-05-25 07:31:29 UTC by John