MCC Displayer

About

MCC Displayer shows you the Merchant Category Code (MCC) when you reach the payment step on checkout pages. MCCs are 4-digit codes that classify businesses by their primary activity - they determine how your credit card rewards are calculated, whether cashback applies, and how transactions appear on your statement.

  Why It Matters

  - Credit Card Rewards: Many cards offer bonus rewards for specific MCC categories (e.g., 3x points on dining, 5% back on groceries)
  - Expense Tracking: Know how your purchase will be categorized before you complete it
  - Business Expenses: Verify merchant classifications for expense reports and tax purposes

  Key Features

  Smart Detection
  - Automatically detects when you're on a payment step (card entry forms, saved payment methods)
  - Works with major payment providers including Stripe, PayPal, Square, Braintree, and Adyen
  - Supports single-page applications with real-time updates

  Intelligent MCC Resolution
  - Domain-specific rules for accurate classification
  - Flow-based detection for multi-purpose sites (e.g., distinguishes between flights vs. hotels on travel sites)
  - Heuristic fallback for unknown merchants

  Customizable
  - Set manual overrides for specific domains
  - Adjustable auto-close timer for the notification badge
  - Import/export rules for backup and sharing

  Privacy-Focused
  - All processing happens locally in your browser
  - No data is sent to external servers
  - No account required

  How It Works

  1. Browse to any checkout page
  2. When you reach the payment step, a badge appears showing the MCC
  3. Hover over the badge for details (category, confidence level, detection source)
  4. Click to access more options or dismiss

  Perfect For

  - Credit card rewards optimizers
  - Small business owners tracking expenses
  - Anyone curious about how merchants are classified