Building Your First Flowcharts

Now that you understand process components and flowchart symbols, it's time to put that knowledge into practice. In this lesson, we'll build flowcharts step by step, starting simple and gradually increasing complexity.

The Flowchart Building Process

Creating a flowchart follows a systematic approach:

Step-by-Step Example 1: Simple Login Process

Let's build a flowchart for a user login process from scratch.

Step 1: Define the Scope

Process: User authentication for a web application Start: User enters credentials End: User is logged in or receives an error

Step 2: List the Steps

1. User enters email and password
2. System validates input format
3. System checks credentials against database
4. If valid, create session
5. If invalid, show error message
6. Redirect to appropriate page

Step 3: Identify Decisions

• Is the input format valid?
• Do the credentials match?

Step 4: Build the Flowchart

[!TIP] Build Incrementally Start with the "happy path" (everything goes right), then add error handling and edge cases. This keeps your flowchart organized.

Step-by-Step Example 2: Password Reset Flow

Let's build a slightly more complex flowchart.

Step 1: Define the Scope

Process: Password reset for a web application Start: User clicks "Forgot Password" End: Password is reset or process is abandoned

Step 2: List the Steps

1. User clicks "Forgot Password"
2. User enters email address
3. System validates email exists
4. System generates reset token
5. System sends reset email
6. User clicks reset link
7. System validates token
8. User enters new password
9. System validates password strength
10. System updates password
11. User logs in with new password

Step 3: Identify Decisions

• Does the email exist in the system?
• Is the reset token valid and not expired?
• Does the new password meet strength requirements?

Step 4: Build the Flowchart

[!NOTE] Security Note Notice that when the email is not found, we show a "generic message" rather than "email not found." This is a security best practice — don't reveal whether an email exists in your system.

Step-by-Step Example 3: API Request Processing

Now let's build a technical flowchart for API request processing.

Step 1: Define the Scope

Process: Handling an incoming API request Start: Request received by server End: Response sent to client

Step 2: List the Steps

1. Request received
2. Parse request
3. Validate authentication token
4. Check authorization/permissions
5. Validate request body
6. Process the request
7. Format response
8. Send response

Step 3: Identify Decisions

• Is the request format valid?
• Is the authentication token valid?
• Does the user have permission?
• Is the request body valid?
• Did processing succeed?

Step 4: Build the Flowchart

Practice: Build Your Own

Exercise 1: File Upload Process

Build a flowchart for a file upload feature with these requirements:

• User selects a file
• System validates file type (only images allowed)
• System validates file size (max 5MB)
• System uploads to cloud storage
• System generates a thumbnail
• System saves metadata to database
• User receives a success or error message

Exercise 2: Shopping Cart Process

Build a flowchart for adding an item to a shopping cart:

• User browses product catalog
• User selects a product
• System checks product availability
• User selects quantity
• System checks if quantity is available
• System adds to cart
• System updates cart total
• User can continue shopping or proceed to checkout

Exercise 3: Code Review Process

Build a flowchart for a code review workflow:

• Developer creates a pull request
• Automated checks run (linting, tests)
• If checks fail, developer fixes issues
• If checks pass, reviewer is assigned
• Reviewer examines the code
• Reviewer approves or requests changes
• If changes requested, developer updates PR
• If approved, code is merged
• Notification is sent to the team

Click to see a sample code review flowchart

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💡 Tip: Use Ctrl + Mouse Wheel to zoom, or click the fullscreen icon

Common Flowchart Patterns

Pattern 1: Validation Loop

Pattern 2: Retry with Limit

Pattern 3: Parallel Processing

Pattern 4: State Machine

Tools for Building Flowcharts

[!TIP] Start with Mermaid Since Mermaid is code-based, your flowcharts can be version-controlled, reviewed in pull requests, and automatically rendered in Markdown files. This makes it ideal for documentation.

Key Takeaways

• Follow a systematic approach: define scope → list steps → identify decisions → draw → review
• Build the happy path first, then add error handling
• Use common patterns like validation loops, retry logic, and parallel processing
• Review your flowchart against the actual process to ensure accuracy
• Mermaid is an excellent tool for creating version-controlled flowcharts
• Practice makes perfect — the more flowcharts you build, the better you'll get

[!SUCCESS] You've Completed Lesson 5 You now know how to build flowcharts from scratch. In the final lesson of this course, we'll explore process optimization — how to use flowcharts to identify bottlenecks and improve processes.