Outage in PostHog US
Realtime destinations: delivery issues
Resolved Minor
September 08, 2026 - Started 9 days ago
- Lasted about 3 hours
Incident Report
Summary AI Generated
**PostHog US – Realtime Destination Delivery Incident (2.7 hours)** An overly strict change to Hog function validation caused valid realtime destinations and transformations to fail, preventing matching events from being forwarded to their destinations. Affected event deliveries during the outage window cannot be replayed, though the underlying events remain intact within PostHog; only a small number of customers were impacted. A fix reverting the validation behavior was merged and deployed, with longer-term work planned to make this type of failure recoverable.
We've identified the root cause: a recent change to Hog function validation was stricter than intended and caused some valid destinations and transformations to fail. When this happens, matching events aren't forwarded to the destination and those deliveries can't be replayed - the events themselves remain safely in PostHog, but the forwarding for the affected window is lost. Only a very small number of customers were affected. We've pulled the complete lists of impacted teams and functions in EU and US to start outbound communication. A fix has been merged that restores the previous behaviour and stops new failures once deployed. We're also scoping a longer-term mechanism to make this class of failure recoverable in the future.
Components affected
PostHog US Destination Delivery (realtime)Trusted by 1,000+ teams
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Latest Updates ( sorted recent to last )
IDENTIFIED
9 days ago - at 09/08/2026 09:39AM
A breaking change in our HogVM caused some destinations to fail. We currently identified the issue and preparing a fix to mitigate the issue.
MONITORING
9 days ago - at 09/08/2026 10:37AM
We've identified the root cause: a recent change to Hog function validation was stricter than intended and caused some valid destinations and transformations to fail. When this happens, matching events aren't forwarded to the destination and those deliveries can't be replayed - the events themselves remain safely in PostHog, but the forwarding for the affected window is lost. Only a very small number of customers were affected. We've pulled the complete lists of impacted teams and functions in EU and US to start outbound communication. A fix has been merged that restores the previous behaviour and stops new failures once deployed. We're also scoping a longer-term mechanism to make this class of failure recoverable in the future.
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