vendor/posthog · vendor documented

PostHog capture treats an epoch timestamp as now

You backfill six months of events. Insights show a spike today. The events are not missing. They are stamped with the time PostHog received them.

timestamp is ISO 8601. An epoch number is a different type. Capture still accepts the request. The historical value is not applied. Missing event or distinct_id is not ingested, and PostHog still returns 200 OK.

timestamp is ISO 8601, not epoch

Send 2026-07-26T06:00:00Z. Segment uses the same shape. Amplitude wants milliseconds. If your pipeline already emits epoch for Amplitude, do not reuse the field on PostHog.

Rule: vendor.posthog.body.timestamp.invalid

Every event needs distinct_id

On a single capture and on every row of batch. PostHog's own docs: a missing name, a missing distinct_id, or an empty distinct_id is not ingested, and you still get 200.

Rule: vendor.posthog.body.distinct_id.missing

What this pack matches

Hosts: posthog.com
Paths: …/e/…, …/capture/…, …/batch/…, …/i/v0/e…
Vendor docs: posthog.com/docs/api/capture

Rules

Codes are stable. A finding in CI, MCP, or the playground lands on the same id.

Field	Required	What it checks	Rule ids	Source
`api_key`	required	It is the project API key, and PostHog rejects the request without it. Fix: Send the project API key from your PostHog project settings.	`vendor.posthog.body.api_key.missing` `vendor.posthog.body.api_key.empty`	docs
`event`	required	It is the name of the event being captured. Fix: Name the event, such as `user signed up`.	`vendor.posthog.body.event.missing` `vendor.posthog.body.event.empty`	docs
`distinct_id`	required	It identifies the person the event belongs to. Fix: Send the same `distinct_id` you use elsewhere for this person.	`vendor.posthog.body.distinct_id.missing` `vendor.posthog.body.distinct_id.empty`	docs
`timestamp`	optional	PostHog documents the timestamp as ISO 8601. An epoch number is read as the ingestion time instead. Fix: Send an ISO 8601 timestamp, such as `2026-07-26T06:00:00Z`.	`vendor.posthog.body.timestamp.empty` `vendor.posthog.body.timestamp.invalid`	docs

Validate a payload

pixellint validate json @payload.json --rulepack vendor/posthog

Or paste it into the playground. Same engine, in the browser, nothing sent anywhere.

cargo install pixellint · npm install pixellint