traceback

The Python traceback module provides utilities for working with error tracebacks in Python programs. It’s particularly useful for debugging and error handling, as it allows you to capture and display the call stack of a program when an exception occurs.

Here’s a quick example:

Python 
>>> import traceback

>>> try:
...     {"a": 1}["b"]
... except KeyError:
...     traceback.print_exc()
Traceback (most recent call last):
    ...
KeyError: 'b'

Key Features

  • Extracts stack traces from traceback objects
  • Formats stack traces for display
  • Prints exceptions and their stack traces to standard error
  • Supports customization of traceback formatting
  • Colorizes traceback output by default in Python 3.13 and later, configurable through the PYTHON_COLORS and NO_COLOR environment variables
  • Captures complete exception information for debugging and logging
  • Works with both caught and uncaught exceptions

Frequently Used Classes and Functions

Object Type Description
traceback.TracebackException Class Captures an exception for later rendering without holding references to traceback and frame objects
traceback.format_exc() Function Returns a string representation of the current exception
traceback.print_exc() Function Prints the current exception to sys.stderr
traceback.extract_tb() Function Returns a StackSummary, which is a list of FrameSummary objects extracted from a traceback object
traceback.format_tb() Function Formats a traceback object as a list of strings
traceback.format_list() Function Formats a list of traceback frames as a list of strings

Examples

Formats and prints the current exception’s stack trace:

Python