Sources versus destinations - the distinction that matters
PostHog's CDP (customer data platform) layer separates sources - external systems sending data into PostHog (Attentive, Impact partner data, Linear for product/engineering context) - from destinations - places PostHog sends event or audience data out to, which is where Microsoft Ads and Amazon Ads sit. Confusing the two during setup is the most common early mistake: an "integration" in PostHog's CDP list is not automatically bidirectional, and each connector has one direction.
What the ad-platform destinations actually sync
| Destination | Typical use | What to confirm before relying on it |
|---|---|---|
| Microsoft Ads | Conversion events or audience segments built from PostHog cohorts, sent for campaign optimization or retargeting | Which event or cohort definitions map to which conversion action on the Microsoft Ads side - this mapping is manual and easy to get subtly wrong |
| Amazon Ads | Similar conversion/audience sync for Amazon's ad ecosystem | Match key and identity resolution - Amazon's audience matching depends on identifiers actually present in your PostHog person properties |
Source connectors worth knowing about
Attentive (SMS/email engagement data), Impact and Impact Partner (affiliate/partnership conversion data), and Linear (engineering issue context) are examples of sources that bring external context into PostHog rather than sending data out. Bringing partner or engineering data alongside product events lets you, for example, correlate a spike in support/error activity with a specific released feature tracked in Linear - without a manual cross-reference every time.
The full connector list and each one's exact field mappings change as PostHog's CDP catalog grows - verify current source and destination availability against PostHog's own CDP docs before scoping an integration plan around a specific connector.
How to verify it worked
- For a destination (Microsoft/Amazon Ads): trigger the conversion event or cohort membership change in PostHog, then confirm it actually appears on the ad platform's side within its documented sync window - not just that PostHog shows the destination as "connected."
- Check the ad platform's own audience size or conversion count against what you expect from the PostHog-side definition - a mismatch usually means an identity-matching or field-mapping problem, not a sync failure.
- For a source (Attentive, Impact, Linear): confirm the incoming data appears as expected properties on the correct person or event in PostHog, and that it is queryable alongside native PostHog events, which is the entire point of bringing it in.