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cowlissdocs

Testing a segment

Preview before you save

Section titled “Preview before you save”

POST /v1/segments/preview runs a definition that does not exist yet over one app’s existing profiles, and answers with the match count and a small sample of members:

Terminal window
cow segments preview --app-id app_website \
  --definition '{"match": "all", "predicates": [{"kind": "trait", "name": "plan", "op": "eq", "value": "free"}]}'

The app is the one the segment would belong to, so the count is the count you get when you save it. The scan is bounded: 1,000 profiles per call, rate-limited per organization. When it hits the cap the count comes back truncated, which is a floor rather than the exact number. A saved segment’s memberCount is always exact.

The dashboard runs the same preview as you build a definition, so the count under the form is the count you will get.

Widening a rule reaches nobody

Section titled “Widening a rule reaches nobody”

Editing a definition recomputes membership across the app the segment belongs to, and so does a push that changes a journey’s inlined segment. Every entry and exit that finds is real and lands on the person’s timeline.

The people already inside a segment enter its journey at one moment only: when somebody turns that journey on and ticks the box, with the count in front of them. See Enable, disable, observe.

Where next

Section titled “Where next”