Open Source Linters
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Browse free open source Linters and projects below. Use the toggles on the left to filter open source Linters by OS, license, language, programming language, and project status.
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Pylint
It's not just a linter that annoys you!
Pylint is a static code analyzer for Python 2 or 3. The latest version supports Python 3.7.2 and above. Pylint analyses your code without actually running it. It checks for errors, enforces a coding standard, looks for code smells, and can make suggestions about how the code could be refactored. Projects that you might want to use alongside pylint include flake8 (faster and simpler checks with very few false positives), mypy, pyright or pyre (typing checks), bandit (security-oriented checks), black and isort (auto-formatting), autoflake (automated removal of unused import or variable), pyupgrade (automated upgrade to newer python syntax) and pydocstringformatter (automated pep257). Pylint isn't smarter than you: it may warn you about things that you have conscientiously done or checks for some things that you don't care about. During adoption, especially in a legacy project where pylint was never enforced. -
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ESLint
The pluggable linting utility for identifying patterns in Javascript
ESLint is an open source tool for identifying and reporting on patterns found in ECMAScript/JavaScript code. ESLint is written using Node.js -
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JavaScript Standard Style
JavaScript style guide, linter, and formatter
JavaScript Standard Style is a JavaScript style guide with linter and automatic formatter. It’s the simple, easy, fuss-free way to get a consistent style in your project. No more hundred-line style configuration files for every module/project; no more messy or inconsistent code; and no more wasting time sending code back and forth between reviewer and contributor. With Standard, your code is automatically formatted, no configuration necessary. With Standard, code clarity and community conventions is paramount. This may not make sense to all projects or development cultures, but does make a lot of sense for open source projects where setting up clear, automated contributor expectations makes a project healthier. -
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golangci-lint
Fast linters Runner for Go
golangci-lint is a fast Go linters runner. It runs linters in parallel, uses caching, supports yaml config, has integrations with all major IDE and has dozens of linters included. ⚡ Very fast: runs linters in parallel, reuses Go build cache and caches analysis results. Yaml-based configuration. Integrations with VS Code, Sublime Text, GoLand, GNU Emacs, Vim, Atom, GitHub Actions. A lot of linters included, no need to install them. Minimum number of false positives because of tuned default settings. Nice output with colors, source code lines and marked identifiers. -
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CSSLint
Automated linting of cascading stylesheets
CSSLint is an open-source CSS code quality tool originally written by Nicholas C. Zakas and Nicole Sullivan. A lint tool performs static analysis of source code and flags patterns that might be errors or otherwise cause problems for the developer. CSSLint is a tool to help point out problems with your CSS code. It does basic syntax checking as well as applying a set of rules to the code that look for problematic patterns or signs of inefficiency. The rules are all pluggable, so you can easily write your own or omit ones you don't want. You can integrate CSSLint into your favorite IDE to make checking your CSS code quality easy. In fact, some IDEs already have CSSLint built-in. Once you're familiar with the CSSLint command-line interface, the next step is to integrate it into your build system. -
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PyChecker is a static analysis tool for finding bugs in Python source code. It finds problems that are typically caught by a compiler for less dynamic languages, like C and C++. It is similar to lint.
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Notepad++ Linter
Linter plugin for Notepad++
A Notepad++ plugin that allows realtime code check against any checkstyle-compatible linter: jshint, eslint, jscs, phpcs, csslint and many others. -
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The purposes of this software are: 1) to check some lint in CA-Clipper source files 2) to create a comprehensive list of functions (with additional info) 3) and to gather some metrics. The Checker makes HTML reports. The software is written in C++ (
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A GUI tool for easily setting up and maintaining PC-Lint for your projects.
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Angular ESLint
Monorepo for all the tooling related to using ESLint with Angular
Monorepo for all the tooling which enables ESLint to lint Angular projects. Follow the latest Getting Started guide on angular.io in order to install the Angular CLI. Create a new Angular CLI workspace in the normal way, optionally using any of the supported command line arguments and following the interactive prompts. As well as installing all relevant dependencies, the ng add command will automatically detect that you have a workspace with a single project in it, which does not have a linter configured yet. It can therefore go ahead and wire everything up for you! -
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Ansible-lint
Best practices checker for Ansible
Ansible Lint is a command-line tool for linting playbooks, roles and collections aimed towards any Ansible users. Its main goal is to promote proven practices, patterns and behaviors while avoiding common pitfalls that can easily lead to bugs or make code harder to maintain. Ansible lint is also supposed to help users upgrade their code to work with newer versions of Ansible. Due to this reason we recommend using it with the newest version of Ansible, even if the version used in production may be older. As any other linter, it is opinionated. Still, its rules are the result of community contributions and they can always be disabled based individually or by category by each user. ansible-lint checks playbooks for practices and behavior that could potentially be improved. As a community-backed project ansible-lint supports only the last two major versions of Ansible. -
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Bootlint
HTML linter for Bootstrap projects
Bootlint is a tool that checks for several common HTML mistakes in webpages that are using Bootstrap in a fairly "vanilla" way. Vanilla Bootstrap's components/widgets require their parts of the DOM to conform to certain structures. Bootlint checks that instances of Bootstrap components have correctly structured HTML. Optimal usage of Bootstrap also requires that your pages include certain <meta> tags, an HTML5 doctype declaration, etc.; Bootlint checks that these are present. Bootlint assumes that you are using Bootstrap's default class names in your webpage, as opposed to taking advantage of the "mixins" functionality of Less or Sass to map them to custom class names. If you are using mixins, Bootlint may report some false-positive warnings. However, there are some Bootlint checks that are applicable even if you are using mixins pervasively. -
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cpplint is a free lint for C++. It checks C++ code looking for hard to see errors while also making comments on the code's style.
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Clj-kondo
A linter for Clojure code that sparks joy
A linter for Clojure code that sparks joy. Clj-kondo performs static analysis on Clojure, ClojureScript and EDN, without the need of a running REPL. It informs you about potential errors while you are typing. To detect lint errors across namespaces in your project, a cache is needed. To let clj-kondo know where to create one, make a .clj-kondo directory in the root of your project, meaning on the same level as your project.clj, deps.edn or build.boot. A cache will be created inside of it when you run clj-kondo. Before linting inside your editor, it is recommended to lint the entire classpath to teach clj-kondo about all the libraries you are using, including Clojure and/or ClojureScript itself. Since clj-kondo now knows about your version of ClojureScript via the cache, it detects that the number of arguments you passed to select keys is invalid. Each time you edit a file, the cache is incrementally updated, so clj-kondo is informed about new functions you just wrote. -
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Dockle
Container Image Linter for Security
Container Image Linter for Security, Helping build the Best-Practice Docker Image, Easy to start. You can install dockle with the asdf version manager with this plugin, which automates the process of installing (and switching between) various versions of github release binaries. With asdf already installed, run commands to install dockle. You can scan your built image with Dockle in Travis CI/CircleCI. Though, you can ignore the specified target checkpoints by using .dockleignore file. Or, if you just want the results to display and not let the test fail for this, specify --exit-code to 0 in dockle command. -
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EDoC++ is both a lint-like tool and a documentation tool that specialises in analysing and documenting the use of exceptions in C++ code.
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Eclint is a plugin for Eclipse, primarily for use with the Eclipse CDT. It provides a framework for using external C/C++ lint tools within Eclipse.
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Ethlint
(Formerly Solium) Code quality & Security Linter for Solidity
Ethlint (Formerly Solium) analyzes your Solidity code for style & security issues and fixes them. Standardize Smart Contract practices across your organization. Integrate with your build system. Deploy with confidence! Solium does not strictly follow Solidity Style Guide. The practices it enforces by default are best practices for the community at large. If you’re using vim with syntastic, and prefer to use a locally installed version of Solium (rather than a global version), you can install syntastic local solium to automatically load the local version in packages that have installed their own. Solium does not strictly adhere to Solidity Style Guide. It aims to promote coding practices agreed upon by the community at large. You can specify rules or plugins to apply as command line options. If you specify one, it overrides its corresponding configuration in the soliumrc file. -
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Gulp Boilerplate
A boilerplate for building web projects with Gulp.js
A boilerplate for building web projects with Gulp.js. This project is no longer maintained, and is offered as-is. It is strongly recommended that you instead use my Build Tool Boilerplate. Concatenate, minify, and lint JavaScript. Compile, minify, autoprefix, and lint Sass. Optimize SVGs. Copy static files and folders into your dist directory. Automatically add headers and project details to JS and CSS files. Create polyfilled and non-polyfilled versions of JS files. Watch for file changes, and automatically recompile build and reload webpages. Gulp Boilerplate makes it easy to turn features on and off, so you can reuse it for all of your projects without having to delete or modify tasks. -
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Haskell Dockerfile Linter
Dockerfile linter, validate inline bash, written in Haskell
A smarter Dockerfile linter that helps you build best practice Docker images. The linter parses the Dockerfile into an AST and performs rules on top of the AST. It stands on the shoulders of ShellCheck to lint the Bash code inside RUN instructions. You can run hadolint locally to lint your Dockerfile. You can download prebuilt binaries for OSX, Windows and Linux from the latest release page. However, if this does not work for you, please fall back to container (Docker), brew or source installation. Configuration files can be used globally or per project. -
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JCSC is a highly configurable checking tool for your Java source code. It checks the compliance to a defineable coding standard like naming conventions and code structure. Also signs of bad coding, potential bugs are found. JCSC is inspired by lint.
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JavaScript Lint is a development tool that validates JavaScript code for best coding practices, finding common mistakes without actually running the script or opening the web page.
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Joker
Small Clojure interpreter, linter and formatter
Joker is a small interpreted dialect of Clojure written in Go. It is also a Clojure(Script) linter. Send HTTP requests, read and parse JSON, work with file system, start external processes etc. Checks for syntax errors, function arity mismatches, unresolvable symbols, unused namespaces, vars, bindings and much more. Joker uses .joke filename extension. Normally exits after executing the script, unless --exit-to-repl is specified before --file <filename> in which case drops into the REPL after the script is (successfully) executed. (Note use of --file, in this case, to ensure <filename> is not treated as a <socket> specification for the reply.) Our goal is to be suitable for scripting (lightweight, fast startup). This is something that Clojure is not good at and my personal itch I am trying to scratch. Also, to provide some tooling for Clojure and its dialects. Joker has linter mode which can be used for linting Joker, Clojure and ClojureScript code. -
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Jsonnet
Jsonnet, the data templating language
A data templating language for app and tool developers. Eliminate duplication with object-orientation or use functions. Integrate with existing / custom applications. Generate JSON, YAML, INI, and other formats. The name Jsonnet is a portmanteau of JSON and sonnet, pronounced "jay sonnet". It began life early 2014 as a 20% project and was launched on Aug 6. The design is influenced by several configuration languages internal to Google, and embodies years of experience configuring some of the world's most complex IT systems. Jsonnet is now used by many companies and projects. Jsonnet is not an official Google product (experimental or otherwise), it is just code that happens to be owned by Google. Jsonnet is open source (Apache 2.0), familiar syntax, reformatter, linter, editor & IDE integrations, and formally specified.
Guide to Open Source Linters
An open source linter is a type of software that helps developers write better quality code. It is designed to detect coding errors, junk code, and other potential problems before the code is compiled. This can help developers spot mistakes quickly and make sure their projects are up to standards.
Open source linters are available for a variety of different programming languages and development tools, including JavaScript, HTML, CSS, Python, Ruby on Rails, and many more. Linters can also be used to check the formatting of code files as well as ensuring they follow established coding conventions. For example, they may remind you not to use spaces instead of tabs or vice-versa.
The main advantages of using an open source linter over commercial options are cost and flexibility. Since the software is free and open source under most licenses (typically MIT), anyone can access it without having to buy or pay for it separately. Additionally, since anyone has access to the source code itself, users have much more control over how they use the tool than with commercial options which may have features locked down or limited in some way.
Additionally, open source linters tend to receive more frequent updates than commercial options due in part to community contributions from experienced developers who want their suggested changes implemented into the project. The larger contributor base also means there are more resources dedicated towards bug fixes should any arise in addition to increasing overall stability of the project itself.
All in all, open source linters are a great way for developers to ensure their code is of the highest quality. They're free and flexible, plus can be used for any programming language or development tool. With their frequent updates and bug fixes, open source linters make it easier than ever before to write clean, secure code.
Features Offered by Open Source Linters
- Syntax Checking: Open source linters check code for syntax errors, ensuring that the code is written correctly. This improves the accuracy of code while minimizing debugging time.
- Static Analysis: Many open source linters provide static analysis capabilities, which identify issues in the code that may not be detected by traditional debugging techniques. Static analysis can detect problems such as inefficient algorithms or memory leaks.
- Code Formatting: Open source linters can help maintain a consistent coding style across projects and teams by checking for common formatting mistakes like incorrect indentation or missing semicolons. By improving readability, this feature makes it easier to collaborate on projects with multiple developers.
- Automated Refactoring: Open source linters can automatically refactor code to adhere to best practices or quickly clean up an existing project. This helps reduce the amount of time spent manually refactoring each piece of code and ensures consistency throughout the project.
- Diagnostic Output: Many open source linters come packaged with diagnostic output options that provide detailed explanations about why certain issues are flagged in the code base. With more comprehensive error messages and suggested fixes, debugging becomes much easier and faster without compromising quality.
- Plugins: Open source linters often come packaged with a large library of plugins that can be used to extend its functionality. Developers can use these plugins to tailor the linter’s behavior, add additional features, and customize it to fit their specific needs.
What Types of Open Source Linters Are There?
- JavaScript Linter: A JavaScript linter is a type of open source linter that checks for errors in JavaScript code. It also helps to enforce coding conventions and best practices, such as avoiding using global variables and keeping variable names consistent across the program.
- CSS Linter: A CSS linter is used to check your cascading style sheets (CSS) for any errors, typos, inconsistencies or coding violations. It can also help detect possible issues with your design before they become an issue on the web page.
- HTML Linter: An HTML linter is an open source tool that validates the syntax of HTML documents and flags any errors or typos within them. This helps to make sure that all content displays properly in a web browser.
- YAML Linter: A YAML linter is an open source tool used to verify the correctness of files written in YAML (Yet Another Markup Language). It checks for both syntax errors and structural problems such as missing properties, invalid types and more.
- XML Linter: An XML linter is a type of open source software which checks for proper structure and syntax in XML documents against an extensible markup language (XML) schema definition language (XSD). This can help developers spot potential bugs early on in their development process.
- JSON Linter: A JSON linter is an open source software which checks for errors in JavaScript Object Notation (JSON) files. It can detect missing braces, improper formatting and other issues that could cause problems with how the data is interpreted.
- PHP Linter: A PHP linter is a type of open source software designed to help developers locate and fix any issues within their codebase. It checks for syntactical errors, basic standards violations and more; helping to identify potential problems before they become serious bugs down the line.
Benefits Provided by Open Source Linters
- Increased Reliability: Open source linters help reduce the chances of introducing errors and bugs into code by verifying its correctness against a set of predefined rules. By consistently checking for errors, open source linters ensure that code is written to a consistent standard throughout the development process.
- Improved Developer Productivity: Developers can quickly identify mistakes in their code and fix them without having to manually go through every line. This helps save time and effort during coding, which can be used instead to focus on other aspects of product development. Additionally, by reducing the possibility of introducing errors, developers can avoid costly rework down the line while still making sure their code meets quality standards.
- Enhanced Code Maintainability: An open source linter creates an environment where any changes made to the codebase are kept consistent with previously established conventions. This helps make it easier for future developers (or yourself at a later date) to maintain your codebase and quickly understand how it works without being bogged down by inconsistencies or unfamiliar conventions or styles.
- Automated Corrections: Most open source linters feature automated corrections that help auto-format your code so that it adheres to predefined conventions. This helps promote faster development cycles since developers won't have to manually reformat their code each time they make a mistake or come back after taking a break from programming for too long. Additionally, automated corrections ensure consistency across different pieces of your project's code architecture, helping prevent subtle but important issues arising from differences in formatting styles between various components and people working on them.
Who Uses Open Source Linters?
- Software Developers: These are users who can take advantage of open source linters to ensure that their software code follows clean, efficient coding conventions.
- Security Professionals: Open source linters enable security professionals to identify vulnerable or malicious code in order to protect the system from any security issues.
- IT Professionals: System administrators and other IT professionals can use open source linters to identify vulnerabilities in the current system setup as well as potential configuration problems.
- Data Scientists & Machine Learning Engineers: These users can make use of open source linters for debugging and validating machine learning algorithms before deployment in a production environment.
- Web Designers: Web designers and developers can benefit from using open source tools such as CSS and HTML validators to check correctness and consistency of the markup language used for web pages.
- Content Creators & Writers: Open source language-specific syntax checkers help writers ensure that they’re creating content without any stylistic errors caused by typos or grammar mistakes.
- Educators & Students: Academic institutions, teachers, and students alike make use of open source linting tools to evaluate the correctness of code submissions when grading assignments or evaluating student projects against best practices.
- Systems Engineers: System engineers can use open source linters to facilitate development of new services and make sure the system setup is maintained in optimal condition.
- DevOps Engineers: Open source linters enable devops engineers to automate certain development tasks and ensure that changes in the system configuration are done according to secure coding practices.
- QA Specialists & Performance Engineers: These users leverage open source linters to detect errors in their code and ensure the quality of the product they deliver. They also use them to measure the performance of the code and identify weaknesses.
How Much Do Open Source Linters Cost?
Open source linters typically do not have a cost associated with them, as they are free to use. Many open source linters are developed and maintained by volunteers in the development community and can be found on popular software repositories. These linters often receive regular updates from their developers, allowing users to stay up-to-date with the latest bug fixes and feature additions. In addition, many open source linters come with comprehensive documentation that allow users to quickly learn how to use the linter without having to spend any money. All of these factors make open source linters an attractive choice for developers looking for an affordable option for linting their code.
What Software Can Integrate With Open Source Linters?
Open source linters can easily integrate with many types of software. For example, source code editors like Visual Studio Code and Atom often have built-in support for linting, enabling users to get real-time feedback on their coding style and structure. Other IDEs (Integrated Development Environments) such as Eclipse can also integrate with open source linters, allowing developers to continuously review their code while they write it. In addition, build systems like Jenkins and Travis CI can be configured to leverage linting tools when running automated builds on projects, helping ensure the quality of the code before it is released in production environments. Finally, command line interfaces such as CLion are also able to interact with these programs and aid developers in producing clean and well-formed code.
Open Source Linters Trends
- Growing Adoption of Open Source Linters: Open source linters are becoming increasingly popular in the software development world. Many developers are turning away from proprietary linters and instead relying on open source tools due to the fact that they are more flexible and cost effective.
- Increased Support for Multiple Languages: Due to the increasing popularity of open source linters, more developers now have access to support for multiple languages. This allows them to easily switch between different languages without having to purchase separate licenses or learn new coding languages.
- Improved Performance: Open source linters are often faster and more efficient than their proprietary counterparts. This is because they tend to be less resource-intensive and easier to configure.
- Enhanced Security: Open source linters offer enhanced security features that allow developers to better protect their applications against malicious code. They also make it easier for developers to audit their code and keep up with security patches.
- Streamlined Processes: Open source linters simplify the process of code review, as they can automatically detect errors and suggest corrections. This allows developers to reduce the amount of manual work involved in ensuring code quality.
How To Get Started With Open Source Linters
Getting started with using open source linters is easy and can help to improve the quality of code written. The first step is deciding which linter is best for a given language or framework. Different languages will have different types of linters, so make sure to pick one that is specifically designed for the language you are working with.
Once you’ve chosen a linter, download it, if necessary, and install it on your workstation. You may need to set up configuration files or other settings specific to the linter tool before it’s ready to use. Depending upon the type of linter, there may be options available that allow users to customize their usage experience by fine-tuning output messages or assigning text colors based off of warnings and errors displayed in the output logs. Some popular linters like ESLint even provide an interactive setup process which allows users select recommended rules and plugins generated specifically for their project type right within the installation wizard.
Now that you have your linter installed, you can start running it against existing codefiles in order to check for any potential issues or bugs contained within them. Many tools are command line based. This means they must be run from a terminal window such as Powershell, Command Prompt, etc. Just input the correct command based on your chosen configuration settings in order review data gathered by the linter results page by page or file by file. You can also set up automation processes that continuously evaluate and monitor code quality throughout development cycles as changes are made and features added/removed from existing projects over time. This way bugs get caught quickly early on during testing phases instead at production stage when issues affect user experience negatively later down the road.
Finally, depending on how much customization was done prior, debugging issues found via analysis from configurable rulesets can range from relatively simple fixes all the way up more complex resolutions requiring further inspection into problem areas. Remember: consult online documentation provided by each library producer first before making any major modification decisions especially when dealing with underlying architecture elements like syntax format structure. With that said, the open source community is full of helpful resources like forums and wikis packed with previously shared solutions useful for quick resolution of commonly encountered problems.
In short, getting started with an open source linter is easy, and it can greatly improve the quality of code written. It only takes a few minutes to set up and configure one, but the payoff can be huge in terms of debugging time saved down the road.