Buglyst Blog
Learn to debug under pressure.
Playbooks for fast pattern recognition, guides for the full investigation, and articles for the engineering judgment around the edges.
17 playbooks · 509 guides · 95 articles · 12 linked practice labs ·skip to practice
Fast pattern recognition for the production failures engineers see most often.
17 playbooks
Debugging Env Var Issues
A concise checklist for incidents where local works but CI, staging, or production changes behavior.
Debugging Cache Stampedes
How to recognize and contain request spikes when cached data expires.
Debugging CORS Origin Bugs
A practical way to inspect origin parsing, credentials, and header behavior.
Debugging Retry Bugs
Retry issues often hide the first failure and create duplicate work.
Debugging Timezone Bugs
Time bugs usually live at day boundaries, DST changes, and unit conversions.
Debugging Pagination Bugs
Pagination bugs hide in boundary math, cursor reuse, and new records arriving between pages.
Structured investigations for the failure modes engineers meet in real systems.
Spring Security 403 Forbidden Error Debugging
A hands-on guide to diagnosing and fixing 403 Forbidden errors in Spring Security applications, covering hidden causes like annotation misconfigurations and role hierarchy issues.
Spring Boot Application Startup Failure: A Practical Debugging Guide
A concise guide to diagnosing Spring Boot startup failures with concrete commands, logs, and root causes.
Spring JPA LazyInitializationException: Root Causes and Fixes Beyond OpenSessionInView
A practical guide to diagnosing and fixing LazyInitializationException in Spring Data JPA, covering real-world causes like serialization, caching, and transaction boundaries.
Diagnosing and Fixing Java OutOfMemoryError: Java Heap Space
A practical guide to diagnosing Java heap OutOfMemoryError in production, covering non-obvious causes like GC overhead, native memory leaks, and permgen/metaspace issues.
Debugging java.lang.StackOverflowError from Recursion
A practical guide to diagnosing and fixing StackOverflowError caused by unbounded recursion in Java, including thread stack analysis, JVM flags, and code patterns that actually cause this.
Hibernate N+1 Select Problem: Detection, Diagnosis, and Fixes
A hands-on guide to detecting and fixing the Hibernate N+1 query problem with real SQL profiling, lazy loading traps, and JPA fetch strategies.
Long-form thinking on debugging habits, observability, and the systems around the bug.
How to Reproduce a Flaky Test: From CI Logs to Reliable Failure
A practical guide to turning intermittent test failures into reliably reproducible bugs, with techniques ranging from loop testing to thread sanitizers.
Property-Based Testing: Finding the Off-by-One That Lived in Production for 18 Months
A concrete story of how switching from example-based tests to property-based tests caught a timing bug that had survived code review, QA, and 18 months of production traffic.
How We Reduced End-to-End Test Flakiness by 80% with Deterministic Seeding
After months of chasing intermittent failures in our CI pipeline, we implemented a three-part strategy — deterministic seeding, isolated state per test, and a structured retry budget — that cut flaky end-to-end test failures by 80%.
Snapshot Testing: The 5 Hidden Failure Modes That Will Break Your CI
Snapshot tests seem like a safety net, but they often hide real bugs, bloat diffs, and silently break your CI. Here are the five failure modes I've seen in production and how to fix them.
Testing Async Code: Avoiding Flakiness and False Positives in JavaScript
Async testing is full of traps: unhandled rejections, race conditions, and tests that pass when they shouldn't. Here's how to write reliable async tests in JavaScript.
Testing Error Handling Code Paths: A Practical Approach
Error handling code is often the least tested and most brittle. Here's how to cover those paths with fault injection, mocks, and chaos engineering.