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Complex properties handle structured data, B2B/SaaS tracking, and automatically captured context. These properties support advanced use cases beyond simple key-value pairs.

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Properties

Items Array

Product data for e-commerce events — id, name, price, quantity, brand, category.

SaaS Properties

B2B/SaaS tracking — accounts, subscriptions, trials, MRR, seats.

Auto-Captured Fields

Click IDs, UTMs, device info, geo — captured automatically.

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Quick Reference

Property TypeDescriptionWhen to Use
itemsArray of product objectsAll e-commerce events (view_content, add_to_cart, purchase)
SaaS propertiesAccount, subscription, trial, payment fieldsB2B/SaaS event tracking
Auto-capturedClick IDs, UTMs, device, geoAutomatically captured — do not set manually

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Items Array

The items array is required for all product-related events. Each item contains product details: 
window._upstack('track', 'purchase', {
  transactionId: 'ORD-12345',
  value: 149.99,
  currency: 'USD',
  items: [
    {
      id: 'SKU-001',
      name: 'Running Shoes',
      price: 89.99,
      quantity: 1,
      brand: 'Nike',
      category: 'Footwear',
      variant: 'Blue / Size 10'
    }
  ]
});

Full Items Reference

See the complete items array specification with all supported fields.

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SaaS Properties

For B2B and subscription-based businesses tracking accounts, subscriptions, trials, and revenue: 
window._upstack('track', 'subscription_started', {
  accountId: 'acct_abc123',
  subscriptionId: 'sub_def456',
  planId: 'plan_pro_monthly',
  planName: 'Pro Plan',
  mrr: 9900,
  billingInterval: 'month'
});

Full SaaS Reference

See all SaaS properties including trial, payment, and seat tracking fields.

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Auto-Captured Fields

Do not include auto-captured fields in your track() calls. The Upstack Pixel and edge API capture these automatically.
Auto-captured fields include:
CategoryExamples
Click IDsfbclid, gclid, ttclid, msclkid, fbc, fbp, ttp
UTM Parametersutm_source, utm_medium, utm_campaign, utm_content, utm_term
Page Contexturl, path, referrer, title, host
Devicedevice_type, viewportWidth, viewportHeight, client_user_agent
Geographiccountry, region, city, postalCode, timezone
Sessionsession_id, event_id, event_time, pixel_id

Full Auto-Captured Reference

See all click IDs (Meta, Google, TikTok, Pinterest, Snapchat, AppLovin, LinkedIn, Microsoft, Reddit, and more), UTM parameters, and context fields.