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
Installing Sentry cross Stack
Making Errors Readable
Setting up Distributed Tracing
Finding Slow Code in Traces
Replaying User Sessions
Correlating Logs with Errors
Profiling Slow Functions
Using Insights Dashboards
Monitoring Uptime, Crons and Metrics
Building Alerts and Dashboards
Debugging with Seer
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.
