Feature Request: More reliable cross-session/cross-device survey wait period enforcement

[ordehi]

Feature request

Is your feature request related to a problem?

The seenSurveyWaitPeriodInDays setting is currently enforced entirely client-side via browser localStorage. This means the wait period only works reliably within a single browser on a single device. Users can see surveys more frequently than intended when they:

• Switch devices
• Switch browsers
• Clear browser storage
• Use incognito/private mode
• Have a custom distinct_id set before PostHog assigns one

A customer recently saw two different surveys within 2 days despite a 30-day wait period configured, because their sessions had different device IDs and isolated localStorage.

Describe the solution you'd like

A more reliable way to enforce survey frequency limits that works across sessions and devices. This could be:

1. Server-side filtering: Track when a user last saw a survey (via $survey_shown events or a person property) and filter surveys server-side before returning them to the client
2. Built-in person property tracking: Automatically set a person property like $last_survey_shown_at when surveys are displayed, and allow targeting surveys based on this property
3. Hybrid approach: Keep client-side as a fast first check, but validate against server-side state for stronger guarantees

Describe alternatives you've considered

Current workaround: Users can implement this themselves by:

1. Setting a person property (e.g., last_survey_seen_at) whenever a survey is shown
2. Targeting surveys to only show when that property is older than the desired wait period (or doesn't exist)

This works but adds implementation overhead for a common use case, and requires users to understand the limitation exists in the first place.

Additional context

From: https://posthoghelp.zendesk.com/agent/tickets/46093

Debug info

Kind: support

Target area: surveys

Report event: http://go/ticketByUUID/e71fd973-697a-4b12-a609-c4ecea954aec

Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/019b74e8-870c-7bca-a101-e91135b4da9a?t=411

Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%22019b74e8-870c-7bca-a101-e91135b4da9a%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D

Location: https://us.posthog.com/project/11653/surveys/019b2d23-fc81-0000-c510-b7025c9163c2

Persons-on-events mode for project: person_id_no_override_properties_on_events

[adboio]

+1 https://posthoghelp.zendesk.com/agent/tickets/44274

[adboio]

gonna try adding the last seen date as a person property, and popping that on the survey internal targeting flag

we can't backfill since it's local-only right now, but:

• we'll always fall back to local storage
• all surveys moving fwd will get this behavior

so it think it's ok - can also add documentation on the behavior

[adboio]

main app: #44164
sdk: PostHog/posthog-js#2835

[adboio]

+1 from NPS https://posthog.slack.com/archives/C011L071P8U/p1767135554614809