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Python linters help developers enforce code standards, catch and fix errors, and preserve code quality, resulting in bug-free Python programs that are easier to read and maintain. This guide will break down the top linting tools for Python developers in terms of their features, pros, cons, and pricing.
- Ruff: ideal for developers seeking an incredibly fast Python linter with hundreds of built-in rules.
- Flake8: a great pick for developers needing an accurate and highly customizable open-source Python linter.
- Codacy: a solid choice for developers seeking a flexible linting tool with support for over 40 programming languages and integrations with some of the top developer tools.
Ruff
Best for developers seeking an incredibly fast Python linter with hundreds of built-in rules.
Ruff is an open-source Python linter by Astral that is free to use and has automatic error correction, hundreds of built-in rules, and several editor integrations. Ruff is known for its speed and is said to be 10-100 times faster than competing linters.
Features of Ruff
Some of Ruff’s top features include:
- 10-100 times faster than other linters
- 700-plus built-in rules
- Replaces Flake8 and other plugins
- Built-in caching
- Auto fix feature
- Editor integrations
While some may consider it more of a strength or pro than a feature, Ruff’s main highlight is speed. The Python linter’s homepage claims it is up to 100 times faster than existing Python linters, making it ideal for developers looking to boost productivity and save time. Ruff supports over 700 lint rules inspired by popular tools like pyupgrade, Flake8, and pysort. Speaking of Flake8, Ruff serves as a viable replacement for the Python tool, plus many other plugins like pydocstyle, pyupgrade, isort, autoflake, and others.
Ruff’s built-in caching eliminates the need to reanalyze unchanged files, while its auto-fix feature provides time-saving automatic error correction. The linting tool also offers editor integrations with VS Code and other popular tools.
Pros of Ruff
Ruff’s pros include:
- Speed
- Auto-fix
- Almost instant results
- Highly configurable
Ruff’s biggest pro is its speed. Many users have raved about how fast it is compared to other linters, and the Ruff claims to have speeds 10-100 faster than the competition. While Ruff’s speedy performance saves developers time, so does its auto-fix feature that automatically corrects code errors so you do not have to fix them manually. Ruff’s optimized algorithms that are written in Rust offer fast execution. The linting tool analyzes code and offers almost instant results, unlike other linters written in Python, which are much slower. Ruff also offers custom configurations that let you craft rules that fit your coding style and needs.
Cons of Ruff
Ruff’s cons include:
- Relatively new
- Plugin support
- Adding custom rules
Since Ruff is a newer linter, its community and following are not as big as other Python linters. As such, you may find less support or resources until it has more time to grow in popularity, and it may experience some growing pains regarding bugs and errors. Another con related to Ruff’s newness to the market is plugin support. Some users have claimed that they are waiting to use Ruff until it supports more plugins. And since Ruff is a compiled tool, some have noted challenges when adding custom rules.
Pricing of Ruff
Ruff is an open-source Python linting tool released under the MIT license and is free to use.
Read: Top Code Profilers for Developers
Flake8
Example of Flake8 Directory Structure
Best for programmers needing an accurate and highly customizable open-source Python linter.
Flake8 is a highly customizable open-source Python linter. Known for its accuracy and minimal false positives, Flake8 promotes code consistency and helps developers ensure their code is more maintainable and readable.
Features of Flake8
Flake8’s main linting features include:
- Adheres to the PEP 8 style guide
- Plenty of customizations
- Extensibility
- Integrations
- Style violations
- Syntax errors
- Code complexity analysis
- Unused imports and variables
Flake8 enforces PEP 8 (Python Enhancement Proposal) style guide compliance. By adhering to standards for naming conventions, indentation, layout, etc., the linting tool promotes code readability and consistency. You can customize Flake8 to fit your project’s specific coding style preferences and standards, plus extend it with plugins to increase adaptability to different coding requirements. The Python linting tool also integrates with multiple core editors and IDEs for added convenience.
Developers can use Flake8 to spot code inconsistencies and style violations to improve readability and maintainability, plus syntax errors like incorrect indentation or missing colons. The popular Python linter also spots complex code blocks that may need simplification or refactoring and unused imports or variables that may cause unnecessary clutter.
Pros of Flake8
Advantages of using Flake8 as a Python linting tool include:
- Open-source
- Solid accuracy
- Widely used
- Many customizations
Flake8’s status as an open-source Python linter is a plus for developers seeking a free linting solution. Its accuracy, which produces minimal false positives, makes developers’ lives easier. Flake8 is also widely adopted and well-known within the Python community. Since many see it as the standard for Python linting, new users may have an easier time finding resources and support if needed. If your development team has unique coding guidelines, Flake8 can accommodate them with custom linting rules to match your project’s preferences and standards.
Cons of Flake8
Disadvantages of using Flake8 include:
- Steep learning curve
- Too rigid
- Output overload
Beginners new to Python linting may need time to adapt to Flake8’s initial setup and features. Some users may find the linter’s adherence to the PEP8 style guide too strict for their coding preferences. Teams working with large codebases may find Flake8’s plethora of linting messages overwhelming to sift through as they look for critical issues requiring the most urgent attention.
Pricing of Flake8
Flake8 is an open-source Python linter that is free to use and released under the MIT license. You may, however, incur costs if you choose to use other development tools alongside Flake8 in your projects.
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Codacy
Best for developers seeking a flexible linting tool with support for over 40 programming languages and integrations with some of the top developer tools.
Codacy (aka Codacy Quality) is a flexible linting tool that supports over 40 programming languages and multiple integrations with top developer tools like Slack, Jira, GitHub, and GitLab. It can help developers spot coding issues like errors and security vulnerabilities and comes in both free open-source and paid plans.
Features of Codacy
Some of Codacy Quality’s top features include:
- Eye-catching user interface
- Automatic checks
- One-click suggestions
- Integrations
- Support for multiple programming languages
- Dashboard
- Custom configurations
- Coding standards
Codacy’s features begin with an intuitive interface that is easy to use and easy on the eyes. The linting tool automatically checks commits/pull requests as they occur and provides instant feedback inside your Git provider (GitHub, GitLab, or Bitbucket). Codacy flags issues in line, offers one-click commit suggestions, and blocks bad merges to help developers optimize code quality with minimal manual effort.
Codacy integrates with Slack for instant notifications when issues are detected, plus other popular tools, such as IDEs and Jira project management software. It also provides versatility with support for over 40 programming languages/ecosystems, has a dashboard that offers instant insights into code quality, custom configurations, and a coding standards feature to provide code quality uniformity across all projects and teams.
Pros of Codacy
Codacy’s strengths include:
- Intuitive interface
- Detailed reporting
- Solid integrations
- Multi-language support
Codacy’s interface is intuitive and easy to navigate. The linting tool’s detailed reporting offers essential insights to help developers quickly fix coding issues. Codacy’s integrations with popular tools like Slack, Jira, IDEs, etc., are another plus, and its support for multiple programming languages makes it a great fit for developers from differing backgrounds.
Cons of Codacy
Codacy’s weaknesses include:
- Cost for advanced features
- Sluggish performance
- Complex configuration
While Codacy Quality does have an open-source plan that is free for unlimited developers, unlocking advanced features like GitHub, GitLab, and Bitbucket integration, unlimited private cloud-based repositories, one-click autofixes, etc. comes at a premium that some users may not feel like paying. Codacy has been noted for being a bit slow to process and complex regarding its configuration settings.
Pricing of Codacy
Codacy Quality offers linting capabilities via the following pricing plans:
- Open-source: Free for unlimited developers.
- Pro: $15 per developer, per month after a 14-day free trial.
The Codacy open-source plan includes unlimited public cloud-based repositories, best-effort CI pipeline analysis, static code analysis for over 40 ecosystems, static analysis for IaC, linter configuration files, integrations (Slack, Jira, and IDEs), API access, Codacy community access, and customer support via email and chat.
The Codacy Pro plan includes GitHub, GitLab, and Bitbucket integration, priority CI pipeline analysis, unlimited private cloud-based repositories, policies, one-click autofixes for GitHub, an organization dashboard, user training, service level agreement, static IP addresses for allowlisting Codacy, enhanced security and AI features, and a dedicated customer success manager.
What to Look for in a Python Linter
To choose the best Python linter, programmers will want to consider several factors as you shop around, beginning with:
- Ease of use
- Minimal learning curve
- Plenty of documentation and community support
- Active update cadence
- Compatibility with Python versions, libraries, and frameworks
- Customizations and configurations
- Integrations with popular developer tools and IDEs
- Budget and licensing requirements
You want a Python linting tool that is easy to set up and use with a minimal learning curve for beginners or experienced developers. While reading reviews on user-friendliness, look for comments on documentation and community support, as both can come in handy. The linter should be actively updated and maintained, too.
The Python linter you choose should be compatible with the Python version, libraries, and frameworks you are using for your project, and it should integrate well with your integrated development environment or code editor. It should be highly configurable and customizable to fit your unique preferences and needs and be known for having solid performance. Other features to look for in the ideal Python linter include type-checking capabilities, error reporting, automatic code formatting, etc. Lastly, ensure that the Python linter meets your licensing requirements. Most Python linting tools have permissive licenses and are open-source and free to use, but you may run into one that does not possess those qualities during your search.
Final Thoughts on the Best Python Linters
The Python linters listed above are some of the best on the market. To find the best Python linter for your software development team, do some follow-up research to ensure it has all of the features you need and meets your requirements for pricing, user-friendliness, community, and support.
Read: 10 Best Python Certifications