Production Debugging with Sentry

These days, every company runs on software of which they can't see the full picture. There are orders that fail quietly at two in the morning, a checkout that takes forever to service one customer, and a nightly job that stops running for a week before anyone even notices. So, we've got these standard monitoring reports that say the servers are all good, even though the business is losing money behind the scenes.

With Sentry, you can debug in production and close that gap. This book takes a live system from silence to something that explains itself by working through a single storefront application built with Python and JavaScript. You install error monitoring, join three runtimes into one distributed trace, record the customer's own session, bring structured logs alongside those traces, and profile the exact function spending the time. Then the book moves on to how to run it well. You set alerts that people act on, not mute. And you can build a dashboard that the team will actually open.You can catch jobs that fail by never starting, and hand difficult issues to Sentry's Seer agent while keeping your own judgement firmly in charge.

Key Learnings

• Instrument a full-stack application so every failure names its file, line and owner.
• Join browser, API and worker into one trace across the network boundary.
• Read a span waterfall and locate the slow span within two minutes.
• Detect and remove N+1 query patterns using trace evidence rather than guesswork.
• Record and mask customer sessions, proving privacy from the stored payload itself.
• Correlate structured logs with traces so caught errors stop disappearing entirely.
• Profile production safely and name the exact function consuming the time.
• Detect silent failures using uptime checks and scheduled job check-ins.
• Derive alert thresholds from real history instead of instinct or round numbers.
• Review an AI root cause analysis critically before accepting any proposed fix.

Table of Content

1. Installing Sentry cross Stack
2. Making Errors Readable
3. Setting up Distributed Tracing
4. Finding Slow Code in Traces
5. Replaying User Sessions
6. Correlating Logs with Errors
7. Profiling Slow Functions
8. Using Insights Dashboards
9. Monitoring Uptime, Crons and Metrics
10. Building Alerts and Dashboards
11. Debugging with Seer
12. Keeping Sentry Healthy

Target Readers

Whether you're an engineer, SRE or tech lead, you'll find everything you need to scale your company. All the tasks are routine, you can reproduce them and verify the results. Basics of application monitoring and knowing the lifecycle of application development is all you need to get through this book.