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Customer’s phone number. E.164 format recommended for best matching. 
window._upstack('track', 'lead', {
  email: 'customer@example.com',
  phone: '+15551234567',  // E.164 format: +[country][number]
  value: 0,
  currency: 'USD'
});
TypeRequiredEvents
stringNoAll events (improves match quality)

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E.164 Format

The E.164 format is the international standard for phone numbers:
  • Start with + followed by country code
  • No spaces, dashes, or parentheses
  • Example: +15551234567 (US), +442071234567 (UK)

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Privacy

Phone numbers are normalized and SHA-256 hashed before being sent to destinations.

email

Customer email — primary identifier.

firstName / lastName

Customer name for identity resolution.