Guide · Open source
How to use clean-code-php: a guide to readable PHP
Updated · written with AI from the project's own documentation and checked against our catalogue data
clean-code-php is a written guide, not a program, that adapts the clean code ideas from Robert C. Martin's book Clean Code to PHP. It is useful for PHP developers, students learning object-oriented design, and teams reviewing code. After reading this guide, you will know how to open the project, what its sections cover, and how to apply its examples to your own code.
Clean Code PHPpiotrplenik/clean-code-php · ★ 12.5k · MIT Install options & downloads Quick start
- 1Get the guide. Clone the repository with git clone https://github.com/piotrplenik/clean-code-php, or open the project page to read it online.
- 2Check your PHP version. Most examples assume PHP 7.1 or newer, so confirm your project meets that before adapting code.
- 3Read the Variables section. Start with naming, since the guide treats clear names as the base of readable code.
- 4Pick one bad example from your code. Find a spot in your project that matches a bad example, such as a vague name or a deeply nested if.
- 5Refactor using the good version as a model. Rewrite the code in the style of the good example, keeping the same behaviour.
- 6Discuss with your team. Use the examples as shared reference points during code review.
What clean-code-php is and who it is for
The project is a set of guidelines. The README states that it is not a style guide, and that not every principle has to be strictly followed. Each section shows a short 'bad' example followed by a clearer 'good' version.
It is best suited to PHP developers who want more readable and maintainable code, students learning object-oriented design in PHP, developers refactoring an existing codebase, and teams that want shared examples for discussing code quality.
- Not a linter or automated formatter: it is only written guidance.
- Not a framework or library: there is nothing to install as a dependency.
- Examples assume PHP 7.1 or newer, though the README notes many developers still use PHP 5.
How to read clean-code-php locally
The README lists no prerequisites. To read the guide offline, clone the repository with the command below, then open the README in any text or Markdown viewer. You can also read it online on the project page.
git clone https://github.com/piotrplenik/clean-code-phpWhat topics the guide covers
The table of contents is organised into sections. Variables covers naming and nesting. Comparison covers identical comparison and the null coalescing operator. Functions covers arguments, side effects, conditionals and type checking. Objects and Data Structures, Classes and SOLID follow, and the guide ends with Don't repeat yourself (DRY).
- Variables: meaningful names, searchable names, explanatory variables, returning early, avoiding mental mapping.
- Functions: keeping arguments to two or fewer, avoiding flags as parameters, avoiding side effects, avoiding singletons.
- Classes: preferring composition over inheritance, avoiding fluent interfaces, preferring final classes.
- SOLID: Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion.
How to apply a bad and good example to your code
Take one example at a time. Find the same pattern in your own code, such as a vague variable name or a function that takes a flag argument. Rewrite it using the good version as a model, then run your existing tests.
The guide also includes a middle ground labelled 'Not bad'. Use it to see how a change can improve code even when the ideal version is not yet practical.
- Pick one section that matches a problem you have seen in review.
- Compare the bad and good code side by side.
- Refactor a small part of your codebase and check that behaviour is unchanged.
Example: replacing magic numbers with named constants
The guide shows that a bare number like 448 or 4 is hard to understand. Its good version defines named constants on the class and uses them in checks, which makes the code searchable and self-describing.
if ($user->access & User::ACCESS_UPDATE) {
// do edit ...
}What people use it for
- Refactoring an older PHP project by rewriting nested conditionals with early returns.
- Teaching object-oriented design, using the SOLID section as course material.
- Setting a shared vocabulary for naming in a team code review.
- Replacing magic numbers with named class constants in permission or flag code.
Frequently asked questions
Is clean-code-php free to use?
Yes. The repository is licensed under the MIT licence. The guide is free to read, clone and share under those terms.
How do I install clean-code-php?
There is nothing to install. It is a written guide, and the README gives one command to clone the repository locally: git clone https://github.com/piotrplenik/clean-code-php. You can also read it on the project page.
What PHP version do I need?
The README says that most examples only work with PHP 7.1 or newer. It also notes that many developers still use PHP 5, so check your project before applying the code directly.
Is clean-code-php a linter or code formatter?
No. The project is only written guidance and does not provide an enforceable linter or automated formatter. If you need automatic checks, you would need a separate tool.
What are good alternatives to clean-code-php?
The project lists clean-code-javascript, which it was inspired by, as a comparable project. Other related references are php-the-right-way and the PHP-FIG PSR standards.
Do I have to follow every principle in the guide?
No. The README says the principles are guidelines, not strict rules, and that not every one has to be strictly followed or is universally agreed upon.
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Our verdict
Use clean-code-php if you want practical, example-based guidance on readable PHP and object-oriented design, or a shared reference for code review and teaching. Pick something else if you need an enforceable linter, a formatter, or a library you can install, since this project provides none of those.
Install options & downloads