Custom Properties

Custom properties let you attach additional data to events, enabling deeper analysis tailored to your business needs.

What Are Custom Properties?

Standard tracking captures basic information:

• Page URL
• Traffic source
• Device type
• Conversion amount

Custom properties let you add your own data:

• Product category
• Customer type
• A/B test variant
• Subscription plan
• Anything else relevant to your business

Use Cases

E-commerce

_sm('conversion', {
  order_id: 'ORD-12345',
  amount: 149.99,
  properties: {
    product_category: 'electronics',
    brand: 'Apple',
    payment_method: 'credit_card',
    coupon_used: 'SAVE10',
    is_first_purchase: 'true'
  }
});

Analysis enabled:

• Revenue by product category
• Conversion rate by brand
• Coupon effectiveness
• New vs returning customer behavior

SaaS

_sm('event', 'feature_used', {
  properties: {
    feature_name: 'export',
    plan_type: 'pro',
    company_size: '50-100',
    user_role: 'admin'
  }
});

Analysis enabled:

• Feature adoption by plan
• Usage patterns by company size
• Admin vs regular user behavior

Media/Publishing

_sm('pageview', {
  properties: {
    article_category: 'technology',
    author: 'jane-doe',
    publish_date: '2024-01-15',
    word_count: '1500',
    has_video: 'true',
    subscriber_only: 'false'
  }
});

Analysis enabled:

• Performance by category
• Author comparison
• Content length impact
• Video vs text engagement

Property Types

Event Properties

Attached to specific events (pageviews, conversions, custom events):

// Properties sent with this specific event
_sm('event', 'add_to_cart', {
  properties: {
    product_id: 'SKU-123',
    product_name: 'Widget Pro',
    price: '49.99'
  }
});

User Properties

Persist across all events for a user:

// Set once, applies to all future events
_sm('set', 'userProperties', {
  customer_type: 'premium',
  signup_date: '2024-01-15',
  account_id: 'ACC-789'
});

Session Properties

Persist for the current session only:

// Set once, applies to all events in this session
_sm('set', 'sessionProperties', {
  entry_campaign: 'winter-sale',
  ab_variant: 'B'
});

Property Limits

Attribute	Limit
Properties per event	50
Unique property names	Unlimited

Value Limits

Attribute	Limit
Property name	64 characters
Property value	256 characters
Property name format	Alphanumeric + underscore

Reserved Properties

Some property names are reserved for Sealmetrics:

Property	Purpose	Set Automatically
_amount	Conversion value	From amount parameter
_currency	Currency code	From currency parameter
_order_id	Transaction ID	From order_id parameter
_label	Event label	From event type
_page_url	Page URL	Yes
_referrer	Referrer URL	Yes
_timestamp	Event time	Yes

Don't use property names starting with underscore (_).

Best Practices

Naming Conventions

// Good: snake_case, descriptive
properties: {
  product_category: 'electronics',
  customer_type: 'premium',
  is_first_purchase: 'true'
}

// Bad: inconsistent, vague
properties: {
  'Product-Category': 'electronics',
  type: 'premium',
  first: 'yes'
}

Value Consistency

// Good: consistent values
customer_type: 'free' | 'pro' | 'enterprise'

// Bad: inconsistent values
customer_type: 'Free' | 'PRO' | 'Enterprise' | 'free' | 'premium'

Use Strings for All Values

// Good: all strings (required)
properties: {
  price: '49.99',
  quantity: '2',
  in_stock: 'true'
}

// Bad: mixed types (may cause issues)
properties: {
  price: 49.99,      // Should be string
  quantity: 2,       // Should be string
  in_stock: true     // Should be string
}

Quick Start

1. Plan Your Properties

Before implementing, decide:

• What questions do you want to answer?
• What data do you need to answer them?
• Which events should carry which properties?

2. Implement Properties

Add properties to your tracking code:

// With pageviews
_sm('pageview', {
  properties: {
    page_type: 'product',
    category: 'electronics'
  }
});

// With events
_sm('event', 'signup', {
  properties: {
    plan_selected: 'pro',
    referral_source: 'friend'
  }
});

// With conversions
_sm('conversion', {
  order_id: 'ORD-123',
  amount: 99.99,
  properties: {
    product_category: 'software',
    payment_method: 'stripe'
  }
});

3. Analyze in Reports

Once properties are flowing:

1. Open any report
2. Click Add Filter
3. Select your custom property
4. Filter or break down by values

Next Steps

Event Properties

Detailed guide to event-level properties.

User Properties

Properties that persist across sessions.

Content Grouping

Group pages using property rules.