our-claude-skills/custom-skills/20-gtm-audit/code/docs/ga4_events.md

GA4 Recommended Events Reference

Automatically Collected Events

Events GA4 collects without configuration:

• first_visit - First time user visits
• session_start - Session begins
• page_view - Page loads (enhanced measurement)
• scroll - 90% scroll depth
• click - Outbound link clicks
• file_download - File download clicks
• video_start, video_progress, video_complete - YouTube embeds

E-commerce Events (Required Parameters)

view_item_list

{
  event: "view_item_list",
  ecommerce: {
    item_list_id: "related_products",
    item_list_name: "Related Products",
    items: [{
      item_id: "SKU_12345",      // required
      item_name: "Product Name", // required
      price: 29.99,
      quantity: 1
    }]
  }
}

view_item

{
  event: "view_item",
  ecommerce: {
    currency: "USD",
    value: 29.99,
    items: [{
      item_id: "SKU_12345",      // required
      item_name: "Product Name", // required
      price: 29.99,
      quantity: 1
    }]
  }
}

add_to_cart

{
  event: "add_to_cart",
  ecommerce: {
    currency: "USD",
    value: 29.99,
    items: [{
      item_id: "SKU_12345",      // required
      item_name: "Product Name", // required
      price: 29.99,
      quantity: 1
    }]
  }
}

begin_checkout

{
  event: "begin_checkout",
  ecommerce: {
    currency: "USD",
    value: 99.99,
    coupon: "SUMMER_SALE",
    items: [...]
  }
}

add_payment_info

{
  event: "add_payment_info",
  ecommerce: {
    currency: "USD",
    value: 99.99,
    payment_type: "credit_card",
    items: [...]
  }
}

purchase

{
  event: "purchase",
  ecommerce: {
    transaction_id: "T12345",   // required, must be unique
    value: 99.99,               // required
    currency: "USD",            // required
    tax: 4.99,
    shipping: 5.99,
    coupon: "SUMMER_SALE",
    items: [{
      item_id: "SKU_12345",     // required
      item_name: "Product Name",// required
      price: 29.99,
      quantity: 2
    }]
  }
}

Lead Generation Events

generate_lead

{
  event: "generate_lead",
  currency: "USD",
  value: 100  // estimated lead value
}

sign_up

{
  event: "sign_up",
  method: "email"  // or "google", "facebook", etc.
}

login

{
  event: "login",
  method: "email"
}

Engagement Events

search

{
  event: "search",
  search_term: "blue shoes"
}

share

{
  event: "share",
  method: "twitter",
  content_type: "article",
  item_id: "article_123"
}

Parameter Validation Rules

Parameter	Type	Max Length	Notes
event name	string	40 chars	No spaces, alphanumeric + underscore
item_id	string	100 chars	Required for e-commerce
item_name	string	100 chars	Required for e-commerce
currency	string	3 chars	ISO 4217 format (USD, KRW, etc.)
transaction_id	string	100 chars	Must be unique per transaction
value	number	-	Numeric, no currency symbols

Common Validation Errors

1. Missing required params: item_id or item_name not in items array
2. Wrong data type: value as string instead of number
3. Duplicate transaction_id: Same ID used for multiple purchases
4. Empty items array: E-commerce event with no items
5. Invalid currency: Currency code not in ISO 4217 format