Operations | Monitoring | ITSM | DevOps | Cloud

Bugs don’t announce themselves politely. They crash your checkout flow, break authentication, or slow your API to a crawl—usually right before your CEO asks how things are going. And when the error inbox is flooded with a hundred variations of TypeError: cannot read property of undefined, figuring out what actually matters can feel impossible.

Even at Sentry, we're not immune to downtime. In a moment of "oh-the-irony," we once took down our own application with a bad migration. We were adding a field to a critical database table, and the migration locked it completely. Since this table was essential to Sentry’s operation, the entire app went down. The website wouldn’t load, ingestion paused—everything ground to a halt.

This guide explains how errors work in PHP and how to debug them efficiently using logging functions and Sentry. The information in this guide is correct for PHP 8 and perhaps above, depending on how much future PHP versions change.

Sentry uses Issue Grouping to aggregate identical errors and prevent duplicate issues from being created, and duplicate alerts being sent. One of the chief complaints we’ve heard from our users is that in some cases the existing algorithm did not sufficiently group similar errors together, and Sentry would create separate issues and alerts, causing unnecessary disruption–or at least annoyance–to developers.