Phan finds bugs in PHP code before you run it. It proves incorrectness rather than correctness, giving you a comprehensive understanding of your type system with minimal false positives.

composer require --dev phan/phan
./vendor/bin/phan --init   # generates .phan/config.php
./vendor/bin/phan          # analyzes your project

Try Phan in your browser →  |  GitHub  |  Releases

Getting Started Install via Composer, generate a config, and run your first analysis. Includes GitHub Actions and GitLab CI examples.

Tutorial for Analyzing a Large Sloppy Code Base A practical walkthrough for introducing Phan incrementally into an existing project without being overwhelmed by warnings.

What Static Analysis Lets You Do An overview of the kinds of bugs static analysis catches that tests and code review miss.

Frequently Asked Questions Common issues when getting started, and how to resolve them.

Annotating Your Source Code V6 The complete guide to PHPDoc annotations in Phan v6: @param, @return, @var, union types, generic types, variance, utility types, assertion annotations, PHP 8.4/8.5 features, and suppression. Includes interactive runnable examples.

About Union Types What union types are, how Phan represents them internally, and how they flow through your code.

Generic Types V6 Using @template for generic classes, interfaces, traits, and functions. Template constraints, variance annotations, and utility types (key-of<T>, value-of<T>, int-range, and more).

Advanced Type System in V6 Intersection types with unknown classes, improved type narrowing, array inference, and union type clamping.

Typing Parameters How Phan handles the interaction between @param annotations and native parameter type hints.

Phan Config Settings Complete reference for all Phan configuration options: file targeting, issue filters, analysis strictness, output formats, and performance tuning.

Using Phan From the Command Line All CLI flags and options for Phan v6, including incremental analysis flags and the -n (no config) mode.

How To Use Stubs Setting up a stubs/ directory to make external code (libraries, extensions) available to Phan without adding it to directory_list.

Externally Generating a List of Files for Phan Controlling exactly which files Phan analyzes using shell scripts or build tools.

Built-in Plugins Reference for all 50+ built-in plugins: what each one checks, how to enable it, recommended starter sets, and plugin-specific configuration options.

Writing Plugins for Phan Creating custom analysis plugins using the PluginV3 API: all 20 capability interfaces, visitors, issue emission, and implementing --automatic-fix support.

Incrementally Strengthening Analysis A step-by-step guide to ratcheting up Phan's strictness over time without drowning in warnings.

Issue Types Reference Complete reference for all Phan issue types, organized by category, with examples and remediation guidance.

Tooling and Suppression Baselines Generating a baseline file to suppress existing issues, batch-adding suppressions, and managing suppressions over time.

Incremental Analysis Re-analyze only changed files and their dependents — 10–50× faster than a full run on large projects.

Speeding up Phan Analysis Configuration and workflow tips for faster analysis: parallelism, file exclusions, polyfill parser, and more.

Memory and Performance Optimizations AST trimming, union type clamping, and tuning Phan for very large codebases.

Phan Helpers Extension Optional C extension providing 2–3× faster AST hashing and type deduplication, with minimal configuration required.

Different Issue Sets On Different Numbers of CPUs Why parallel analysis can produce slightly different results, and how to get consistent output.

Editor Support Setting up Phan in VS Code, Vim, Emacs, and other editors. Includes how to write editor integrations using the language server protocol.

Using Phan Daemon Mode Low-latency single-file analysis for editor integrations. Phan stays running in the background and responds to file analysis requests.

PHP 8.4 and 8.5 Support Phan's support for property hooks, #[Deprecated], #[NoDiscard], typed class constants, and the PHP 8.5 pipe operator.

Migrating to Phan V6 Breaking changes, removed config options, and CLI flag changes when upgrading from Phan v5 to v6.

Developer's Guide To Phan Architecture overview, how to set up a development environment, and how the analysis pipeline works.

Writing Plugins for Phan Creating custom analysis plugins using the PluginV3 API: visitors, capabilities, issue emission, and autofix support.

How To Create a Phan Release Checklist for cutting a new Phan release: version bump, changelog, phar build, signing, and publishing.

Looking for older documentation? Phan v5 is in maintenance mode (critical bug fixes only). The pages below still exist but have been superseded by v6 versions.

Phan V5 Documentation — Archived v5 annotation guide, generic types guide, and legacy plugin API docs.