Auto-Properties

Properties automatically attached to events by SDKs and the backend. All auto-properties are prefixed with $ to distinguish them from user-defined properties.

You never need to set these manually — the SDK and server add them automatically. Sending them yourself creates duplicates.

SDK-enriched (client-side)

Attached by the Web SDK before sending to the API.

Property	Source	Description	Example
`$url`	Web SDK	Current page URL	`https://app.com/pricing`
`$referrer`	Web SDK	Document referrer	`https://google.com`
`$title`	Web SDK	Page title	`Pricing — Acme`
`$screen`	SDK	Screen dimensions	`1920x1080`
`$utm_source`	Web SDK	UTM source parameter	`google`
`$utm_medium`	Web SDK	UTM medium parameter	`cpc`
`$utm_campaign`	Web SDK	UTM campaign parameter	`spring_sale`
`$utm_term`	Web SDK	UTM term parameter	`analytics+software`
`$utm_content`	Web SDK	UTM content parameter	`banner_a`
`$sdkVersion`	SDK	SDK version string	`1.2.0`

UTM parameters are parsed from the page URL on each event. They persist for the session once captured.

Server-enriched (ingestion workers)

Added by event workers after BatchCreate — not present in the SDK payload.

Property	Description	Example
`$geo.country`	Country from IP geolocation	`US`
`$geo.city`	City from IP	`San Francisco`
`$geo.region`	Region/state from IP	`California`
`$browser`	Browser name	`Chrome`
`$browserVersion`	Browser version	`120.0.0`
`$os`	Operating system	`macOS`
`$device`	Device type	`desktop`, `mobile`, `tablet`
`$botScore`	Bot likelihood (0–1)	`0.02`

Server enrichment requires the request to include client IP (standard behind a load balancer). Self-hosted deployments must forward X-Forwarded-For correctly.

Usage in queries

Reference auto-properties in Insights filters and breakdowns exactly like custom properties:

Breakdown by country


Events:      page_view
Breakdown:   $geo.country
Aggregation: Unique users

Filter to Chrome users


Events:      purchase
Filter:      $browser = "Chrome"
Aggregation: Sum (revenue)

UTM campaign performance


Events:      signup_completed
Breakdown:   $utm_campaign
Aggregation: Count
Filter:      $utm_source = "google"

Exclude bots


Events:      page_view
Filter:      $botScore &lt; 0.5
Aggregation: Unique users

Auto-properties vs custom properties

	Auto-properties	Custom properties
Prefix	`$`	None
Set by	SDK or server	Your code
Available on	All events	Events where you send them
Schema	Fixed	Any key-value

Custom properties you define (e.g. plan, product_id) are separate from auto-properties and appear without the $ prefix.

Privacy

Property	Privacy consideration
`$url`	May contain query params with sensitive data — review URL structure
`$geo.*`	Derived from IP — disclose in privacy policy
`$referrer`	May reveal referring site with user context
`$botScore`	Internal signal — safe to use for filtering

For GDPR/CCPA compliance:

Review which auto-trackers are enabled — see Auto-tracking
Disable form and click trackers if element text may contain PII
Add consent before calling init() if required by your jurisdiction
Geo enrichment uses IP address — document this in your privacy policy