The Best Tools to Debug Python

Python is a high-level programming language often used for building desktop GUI applications, websites, and even web-based applications. It is one of the top ten programming languages in the world today, and its popularity stems from its simple syntax that makes your code highly readable.

Here is our list of the best tools to debug Python applications:

1. PyCharm – EDITOR’S CHOICE This is a comprehensive python IDE that can develop, debug, and manage all kinds of Python applications. Offered in both a paid version and a free Community Edition. Runs on Windows, macOS, and Linux. Download a 30-day free trial of the Professional Edition.
2. PDB This is an interactive source code debugger that is a part of Python's standard library.
3. Pyringe This Python debugger tool injects code into Python processes while they are running to inspect the state and for effective debugging.
4. Pyshield This is an integrated development platform that supports Python debugging and script editing.
5. Python Tools for Visual Studio This is a free extension developed by Microsoft's community for debugging Python applications.
6. PyScripter This is another open-source Python IDE that comes with many competitive features.
7. PyDev This is a third-party Python plugin for Eclipse that doubles up as an IDE as well.
8. Vprof This command generates statistics about your program's code, so you can understand where more resources are spent and optimize them accordingly.
9. PySnooper This tool aims to simplify the process of debugging for complex and legacy Python applications.

Further, it supports multiple programming paradigms, a dynamic type system, automatic memory management, a robust standard library, and test-driven development, all of which simplify even complex applications. Its compatibility across major platforms and systems and support for many open-source tools and frameworks add to its popularity.

Due to these reasons, many applications today are developed in Python. However, like every application, these are prone to issues, and they have to be debugged. That said, debugging doesn't have to be arduous when you use the right tools geared specifically for your applications. Let's take a deep dive into each of these tools so you can decide the one that would be ideal for debugging your Python applications.

The Best Tools to Debug Python Applications

What should you look for in a debugger for Python? 

We reviewed the market for Python debugging tools and analyzed options based on the following criteria:

• An integrated development environment that can guide fault-free coding
• A code display that color codes keywords
• Code element completion or a keyword selection list
• A scanner to verify existing code and spot syntax errors or security weaknesses
• Code library management with version control
• A free trial or a demo for a risk-free assessment opportunity
• Value for money from a Python code analyzer that is offered at a fair price

With these selection criteria in mind, we identified a shortlist of comprehensive Python checkers that spot obvious syntax mistakes and also scanners that can be used for vulnerability detection.

1. PyCharm

PyCharm is a comprehensive IDE platform that enhances the productivity of professional Python developers and enables them to focus on the larger picture.

Key Features:

• Offers smart code completions to reduce time and effort
• Supports on-the-fly error highlights and, accordingly, suggests quick fixes
• Provides automated code refactoring
• Comes with rich navigation capabilities
• Its smart search feature makes it easy to jump to any class, file, symbol, or IDE window
• Get to the declarations, methods, tests, and more with just one click
• Comes with an integrated debugger and test runner
• Allows you to create and run tests with a GUI-based test runner
• Saves time with a unified UI for Git and other version control systems
• Provides access to many database tools such as Access, Oracle, PostgreSQL, SQL, and more
• Makes it easy to edit SQL code, run queries, browsing data, etc.
• Provides frame-specific support for Django, Flask, Pyramid, web2py, and more
• Supports JavaScript, CoffeeScript, TypeScript, CSS, and HTML
• Supports live edits and previews
• Integrates with IPython Notebook, an interactive Python console, and other package libraries such as Anaconda, Matplotlib, and Numpy
• You can use it on Windows, macOS, or Linux with a single license key

Why do we recommend it?

PyCharm is recommended for its comprehensive IDE features tailored for Python development, offering smart code completions, error highlights, and automated refactoring, making it a top choice for professional developers.

Who is it recommended for?

It's ideal for Python developers seeking a robust, all-in-one IDE with advanced features like integrated debugging, test running, database tools, and support for web development frameworks.

Pricing: Pycharm comes in two editions, namely, PyCharm Professional and PyCharm Community Edition. The Community edition is open-source and hence, free. PyCharm Professional, on the other hand, includes additional features and costs $199/year for just the IDE and $649 for the all-product pack.

Download: Click here to download a trial version of PyCharm Professional and here for the open-source community edition.

2. PDB

PDB is an interactive source code debugger that comes as a part of Python's standard library. In particular, this is a valuable tool when you have to debug in an environment that doesn't have any GUI debugger.

Key Features:

• Interacts with you and waits for your inputs
• Supports setting conditional breakpoints
• Inspects stack frames and source code listings to enable you to find and fix bugs quickly
• Extensible, as you can modify the Pdb class
• You can stop the program at a specific point to debug it
• Evaluate an expression and call the functions you choose
• Supports post-mortem debugging
• Enables you to raise an auditing event with no arguments
• Most of its commands can be abbreviated to one or two letters for easy remembrance. Thus, for example, the help is “h”, the down count is “d”, and so on
• Supports aliases, which in turn can have parameters for adaptability to the given context
• Allows you to enter multiple commands in the same line, provided they are separated by “;”

Why do we recommend it?

PDB is an integral part of Python's standard library, offering a lightweight, interactive source code debugging experience, making it highly effective for environments lacking GUI debuggers.

Who is it recommended for?

This tool is best suited for Python developers who need a simple, integrated debugger without the need for additional installations or complex setups.

Pricing: 100% FREE

Download: Click here for the source code.

3. Pyringe

Pyringe is a commonly-used debugger that allows you to inject additional Python code into live processes to understand their current state so that you can debug the issue quicker.

Key Features:

• Requires gdb configured with “–with-python” and must be version 7.4 onwards
• Helps to inspect data without stopping a program
• The debugger functions are also Python code exposed to REPL, so you can modify them if you choose to
• Inspects the state of an application or process even when it is being used live, giving you a good idea of the problem in real-time
• Returns information such as threads and tracebacks and inspects locals, globals, and builtins of running functions

Why do we recommend it?

Pyringe stands out for its unique ability to inject code into running Python processes, allowing developers to inspect application state in real-time, which is crucial for effective debugging.

Who is it recommended for?

It's recommended for advanced Python users and developers who require the capability to inspect and debug live code without stopping the application.

Pricing: 100% FREE

Download: Click here to download Pyringe.

4. Pyshield

Pyshield is an integrated development platform that supports Python script editing and debugging, besides running encrypted Python scripts.

Key Features:

• Highlight syntax to reduce the chances of errors
• Supports code block fold
• Enables you to jump to the definition of the symbol when needed
• Search for all references of a symbol across multiple files and directories
• Executes the script and takes you to the line of the script
• Comes with a GUI for easy debugging
• Works with encrypted Python scripts as well
• Runs on Windows XP, Windows 7 (x86 and amd64), Ubuntu i686, and x86_64

Why do we recommend it?

Pyshield's integrated development platform, which supports both script editing and debugging, is ideal for working with encrypted Python scripts, offering syntax highlighting and other useful editing features.

Who is it recommended for?

This tool is perfect for developers who need an IDE that supports encrypted script execution and provides a GUI for debugging Python applications.

Pricing: Contact partners and software vendors from this list to buy it from your preferred entity.

Download: Click here for the download form.

5. Python Tools for Visual Studio

This debugger was developed as an extension for Visual Studio by Microsoft, with help from its community. It supports editing and debugging Python applications.

Key Features:

• Comes with an interactive development environment for Python apps
• Supports familiar frameworks such as Django and Flask
• Provides tooltips, auto-completion, and code snippets for improved productivity
• Supports third-party libraries such as pip, PyPl, and other virtual environments
• Interactively diagnoses issues for quick identification and fix
• Works well on both Windows and Linux
• Visually steps through your code for quick diagnoses
• Allows you to view or modify the program state at any time
• Uses Git as the default source control
• Makes it easy to create and clone repositories from GitHub or Azure DevOps
• Uses the integrated Git tool to commit and push changes to your code
• Enables you to manage branches and resolve merge conflicts
• Executes unit tests directly from the test window, so you don't have to leave the editor at any time

Why do we recommend it?

As a native extension in Visual Studio, this tool offers a seamless debugging experience for Python applications, with support for popular frameworks and excellent integration with Git and other services.

Who is it recommended for?

Python developers who use Visual Studio and seek an integrated environment for Python development with powerful debugging and editing capabilities will find this tool particularly useful.

Pricing: 100% FREE

Download: Click here to download this tool from the Git repository.

6. PyScripter

PyScripter is a free and open-source Integrated Development Environment (IDE) that comes with many advanced features for interactive debugging and development.

Key Features:

• It is based on Unicode
• Provides support for Python source files
• Highlights braces and syntax for HTML, XML, and CSS files
• Offers code completion tips and context-sensitive help for Python keywords
• Accepts files that are dropped from the Explorer
• Supports split-view and side-by-side file editing
• Provides search and replace features
• Comes with parameterized code templates
• Converts line breaks in Windows, Unix, and Mac
• Integrates well with popular tools such as PyLint
• Makes it easy to configure and browse Python paths
• Supports persistent configurable IDE options
• Enables you to find and replace code quickly, integrate regular expression testing, find definitions and references, and more

Why do we recommend it?

PyScripter is a versatile, open-source Python IDE offering advanced features like code completion and side-by-side editing, making it an excellent choice for interactive debugging and development.

Who is it recommended for?

It's well-suited for Python programmers who prefer a free, open-source IDE that provides comprehensive coding and debugging features.

Pricing: 100% FREE

Download: Click here to download from GitHub.

7. PyDev

PyDev is an IDE plugin for Eclipse that can be used for editing and debugging Python code. It also comes loaded with many debugging features.

Key Features:

• Supports code refactoring and analysis
• Enables code completion with auto import
• Allows you to debug scripts that are launched within and outside Eclipse
• Supports an interactive debugging console
• Highlights basic syntax
• Provides smart indent and dedent, comment blocks, commenting and uncommenting, code folding, code coverage, and more to ease the debugging process
• Offers tabs or spaces preferences
• Present keywords as auto-completion even as you type, thereby making you highly productive
• Supports CPython, Jython, and IronPython as well

Why do we recommend it?

PyDev shines as a plugin for Eclipse, offering features like code refactoring, analysis, and an interactive debugging console, making it a robust choice for Python development within the Eclipse ecosystem.

Who is it recommended for?

This tool is ideal for developers who are comfortable with Eclipse and require an integrated Python development and debugging environment within this platform.

Pricing: It is available as Eclipse's public license.

Download: Click here to download PyDev.

8. vprof

vprof is a command that generates statistical reports to show where your resources are expended the most. Specifically, it tells you which lines of code are taking more time and resources, and you can refactor or debug those code snippets to improve your application's performance.

Key Features:

• The reports show lines and functions to give you a more comprehensive understanding of your code performance
• You can see a list of time-based samples that were recorded and the amount of CPU time spent on those recorded samples
• Next, vprof displays function-level time consumption followed by line-level time consumption
• Helpful in evaluating the efficiency of algorithms and the performance of your code
• It can be extended to view running time and memory usage, besides CPU resources

Why do we recommend it?

vprof is notable for its visual reporting on code performance, offering insights into resource consumption, which is invaluable for optimizing Python applications.

Who is it recommended for?

Developers focused on performance optimization and code efficiency will benefit greatly from vprof's detailed profiling and resource usage analysis.

Pricing: It is open-source and available on GitHub.

Download: Click here to download vprof.

9. PySnooper

PySnooper simplifies debugging complex and legacy Python projects by automatically generating logs on the source code lines and functions that were examined.

Key Features:

• Makes it easy to debug complex and legacy Python projects
• Displays the lines that were executed
• For example, you can see the values of local variables through this debugger
• Requires no additional setup. Simply add “pysnooper.snoop()” before any line in any function to trace the performance of that entire function
• Allows you to redirect the output to a specific file
• Enables you to pass a stream or a callable within the function
• Displays the values of some related variables, even if they are not local to the function
• You can use prefixes when needed
• Enables you to remove all machine-related data for easy comparison with other traces
• Supports multithreaded applications
• You can use this tool for an entire class, and it will cover all the functions mentioned in that class
• Enables you to customize the repr of an object
• Allows you to truncate values to any digit
• Timestamps can display the start time or the wall time, based on your requirements

Why do we recommend it?

PySnooper excels in simplifying the debugging process for complex and legacy Python projects by automatically generating detailed logs, making it a valuable tool for quick and efficient debugging.

Who is it recommended for?

It's particularly useful for developers working on legacy or complex Python projects who need a straightforward, easy-to-use debugging tool for rapid problem-solving.

Pricing: It is free and available on GitHub.

Download: Click here to download PySnooper.

Thus, these are some of the tools that can be used to debug Python code and applications. Of course, there are a lot of variations among these tools, so make sure to choose the one that best fits the application you're debugging and your personal preferences. For example, if you prefer to read through the results in a code, go for something like vprof. On the other hand, if you want a visual debugger, PyCharm is a good choice.

Conclusion

To conclude, Python applications are popular because this programming language is highly readable, and its syntax is intuitive and straightforward.  Since they are integral to an organization's operations, it becomes necessary to test them extensively before production.

The good news is there are many Python debugging tools available today that can test every line of source code, assess its resource usage, and point out the slow-performing snippets. Accordingly, you can refactor the code, add more resources, or take any other desired action to ensure that your Python applications are reliable and have high performance.

We hope the above-mentioned tools come in handy for you.

Python Debugging Tools FAQs