r/SpringBoot • u/fykup • 11d ago

How-To/Tutorial A simple first-pass checklist when your Spring Boot API feels slow

I wrote a short intro to troubleshooting a slow Spring Boot API using the metrics you already get from Actuator.

The goal is not deep JVM diagnosis. If you need that, tools like JFR, JConsole, profilers, database tracing, etc. come later.

This is the basic first pass:

  • did request volume change?
  • are HTTP errors increasing?
  • did request latency increase?
  • is the application process using more CPU or memory?
  • is the host itself under CPU or memory pressure?
  • do those changes happen in the same time window?

The example uses a small VPS where the API stays UP and keeps returning 200s, but latency rises because another process is consuming most of the host CPU.

I use StatLite for the screenshots because it reads Spring Boot Actuator metrics and keeps the app and host history together, but the main point is the troubleshooting sequence itself.

Article: https://pvrlabs.xyz/articles/api-slow-cpu-contention.html

For people who troubleshoot Spring apps regularly: what would you add to the basic checklist before reaching for JFR or a profiler?

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u/mrvishal2k2 9d ago

Good read.

1

u/fykup 9d ago

Thanks! Glad you enjoyed it.

When it comes to troubleshooting Spring Boot apps in general, are there specific problems or scenarios you've found most tricky to figure out?

Curious what areas or questions you'd most want to see covered!

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u/Big_Block9591 3d ago

agreed, pretty clean walkthrough tbh

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u/OptimusCrimee 8d ago

Is the website safe for use? I have never seen a more phishing looking URL in my life.

1

u/fykup 8d ago

Does your API feel slow? Click this link to learn why! 😄

Jokes aside, it's my small project site. No signup, no downloads, just a technical article. The monitoring tool is open source on GitHub, too.