Logging for PHP: Best Solutions and Libraries for Your Website

Logging for PHP: Best Solutions and Tools

Logging is one of the key tasks when developing any web application in PHP. Without high-quality logging, it is impossible to effectively debug code, track errors in a production environment, and analyze user behavior. In this article, we will look at the best libraries and tools for logging in PHP, their features, and usage examples.

Why is proper logging important?

A simple call to error_log() or writing to a file via file_put_contents() ceases to be sufficient when a project grows. Modern solutions offer:

• Support for PSR-3 (logging interface standard);
• Flexible handlers (files, DB, syslog, email, Slack);
• Message formatting (JSON, plain text, HTML);
• Log levels (debug, info, notice, warning, error, critical, alert, emergency);
• The ability to filter and rotate logs.

1. Monolog — The De Facto Standard

Monolog is the most popular library for logging in PHP (over 300 million downloads on Packagist). It is fully compliant with PSR-3 and supports dozens of handlers and formatters.

Installation

composer require monolog/monolog

Usage Example

<?phprequire 'vendor/autoload.php';

use Monolog\\Logger;use Monolog\\Handler\\StreamHandler;use Monolog\\Handler\\FirePHPHandler;

// Create the logger$log = new Logger('my_app');$log->pushHandler(new StreamHandler(__DIR__.'/app.log', Logger::WARNING));$log->pushHandler(new FirePHPHandler());

// Log messages$log->warning('Warning: request limit exceeded');$log->error('Database connection error', ['db' => 'mysql', 'time' => 1.5]);?>

Key Features

• Handlers: StreamHandler, RotatingFileHandler, SyslogHandler, SwiftMailerHandler, SlackHandler, etc.
• Formatters: LineFormatter, JsonFormatter, HtmlFormatter, LogstashFormatter.
• Processors: adding context (IP, URI, session) to each message.
• Support for logger groups and channels.

Monolog is ideal for large projects, frameworks (Symfony, Laravel use it by default), and microservice architecture.

2. KLogger — A Lightweight Alternative

KLogger is a simple but effective library for those who don't need hundreds of handlers. It implements PSR-3 and works out of the box.

Installation

composer require katzgrau/klogger

Usage Example

<?phprequire 'vendor/autoload.php';

use Katzgrau\\KLogger\\Logger;

$log = new Logger(__DIR__.'/logs');$log->info('User registered', ['user_id' => 42]);$log->debug('Debug: API request', ['url' => '/api/v1/data']);?>

Features

• Automatic log rotation by date;
• Minimal number of dependencies;
• Support for log levels;
• Simple API (just a few methods).

KLogger is suitable for small projects, scripts, and applications where simplicity is important.

3. Analog — Flexible and Minimalistic

Analog is a library that allows you to easily change the logging method without modifying the code. It uses the concept of a "machine" that determines where and how to write logs.

Installation

composer require analog/analog

Usage Example

<?phprequire 'vendor/autoload.php';

use Analog\\Analog;use Analog\\Handler\\File;

// Configure writing to a fileAnalog::handler(File::init(__DIR__.'/app.log'));

// LogAnalog::warning('Update required');