Debugging Tools in Python

Python ships with pdb, and the built-in breakpoint() call drops into it. ipdb adds IPython features such as tab completion and syntax highlighting, and PuDB provides a full-screen console interface with variables, stack and source visible at once. icecream replaces print debugging by printing expressions alongside their values and source location.

Profilers answer different questions. py-spy is a sampling profiler written in Rust that attaches to a running process without code changes, which makes it safe for production. pyinstrument shows a readable wall-clock call tree, useful for finding where a request spends its time. Scalene profiles CPU, GPU and memory line by line and separates Python time from native code time. memray tracks memory allocations, including those inside native extensions, and VizTracer records every function call into a timeline you can browse. For web apps, django-debug-toolbar and flask-debugtoolbar show SQL queries and timing per request, and django-silk records them for later inspection.