Date: August 5, 2026
Status: Resolved
Following a routine security patch release, documentation pages across hosted Fern sites displayed a "Failed to render this content" placeholder in place of page content. Sites, navigation, API references and search remained online. The issue lasted approximately 85 minutes and was fully resolved by 4:20 PM ET. No customer data was lost or modified.
2:42 PM – A routine release containing a security patch was deployed to production. CI and pre-release validation had passed.
2:55 PM – Reports of content failing to render; issue confirmed and investigation began.
3:00–4:00 PM – Rolled back the production deployments and reverted the change. Because rendered content is cached durably, sites continued to serve the affected output until caches were cleared.
4:00–4:20 PM – Caches purged and revalidated; sites recovered. All customer domains confirmed resolved by ~4:20 PM.
Later that day – Underlying defect fixed and the security patch safely re-applied, with cache invalidation forced.
A dependency upgrade in the service that compiles documentation pages caused page content to fail to compile. Pre-release validation did not catch it because the pages it checked were served from cache and never recompiled against the new code. Because rendered content is cached durably across deployments, the affected output continued to be served after rollback until caches were purged.
We rolled back to a known-good deployment, reverted the upgrade, and purged cached content to restore all sites. The underlying defect was fixed and the security patch safely re-applied the same day.
Page content on hosted documentation sites replaced with an error placeholder
Duration: ~85 minutes (2:55 PM – 4:20 PM ET)
Sites, navigation, and search remained available
No data loss, and no customer content was modified
Cached page content is now tied to the deployment that produced it, so a release can never serve content generated by different code
Releases are now blocked unless the exact rendering build going live successfully compiles a real page
Rendering errors now report specific detail
Add automated post-deploy checks against live sites to detect rendering failures immediately
Expand pre-release validation coverage across all sites
