Logs

Laravel

If you use Laravel, Bref will automatically configure Laravel to log to CloudWatch via stderr (LOG_CHANNEL=stderr) with the Bref\Monolog\CloudWatchFormatter formatter. You don’t have to do anything.

If you have a custom log setup (e.g. using the stack channel), you should ensure that the stderr channel is included in your stack with the Bref\Monolog\CloudWatchFormatter formatter.

With this formatter, logs will contain structured data that can be filtered in CloudWatch Logs Insights. For example, you can filter by log level or exception class.

Symfony

If you use Symfony, Bref will automatically configure Symfony to log to CloudWatch via stderr with the Bref\Monolog\CloudWatchFormatter formatter. You don’t have to do anything.

This is done by the Bref\SymfonyBridge\BrefSymfonyBridgeBundle bundle, which Symfony Flex adds to config/bundles.php when installing bref/symfony-bridge. If it is missing from that file, add it:

return [
    // ...
    Bref\SymfonyBridge\BrefSymfonyBridgeBundle::class => ['all' => true],
];

If you have a custom log setup, you should ensure that logs are sent to stderr (e.g. using the stream handler with php://stderr) with the Bref\Monolog\CloudWatchFormatter formatter (bref.cloudwatch_formatter service).

With this formatter, logs will contain structured data that can be filtered in CloudWatch Logs Insights. For example, you can filter by log level or exception class.

PHP

You can use Monolog  to write logs to CloudWatch via stderr:

$log = new Monolog\Logger('default');
$log->pushHandler(new StreamHandler('php://stderr', Logger::INFO));
 
$log->warning('This is a warning!');

Bref provides a formatter optimized for CloudWatch, it is highly recommended to use it:

composer require bref/monolog-bridge

$log = new Monolog\Logger('default');
$handler = new StreamHandler('php://stderr', Logger::INFO);
$handler->setFormatter(new Bref\Monolog\CloudWatchFormatter);
$log->pushHandler($handler);
 
$log->warning('This is a warning!');

For simple needs, you can replace Monolog with Bref’s logger , a PSR-3 logger designed for AWS Lambda:

$log = new \Bref\Logger\StderrLogger();
 
$log->warning('This is a warning!');

Bref Cloud

You can view, search and tail logs in the Bref Cloud  dashboard:

You can also search logs from the terminal with bref logs:

# Logs of the last hour
bref logs --env=prod
# Logs of the last day of the "web" function that contain "payment" and "failed"
bref logs --env=prod --since=1d --function=web --search="payment failed"
# Between two dates (UTC), with the stack traces of exceptions
bref logs --env=prod --since="2026-09-23 14:00" --until="2026-09-23 15:00" --full

bref logs shows one line per log entry. It hides the lines that Lambda and PHP-FPM write on every invocation (START, END, REPORT…), use --all to include them.

Run bref logs --help for all the options. Add --json for machine-readable output. To use the command outside the project directory, set the application with --app and --team. bref logs is also designed for AI agents.

Serverless CLI

You can view logs in the CloudWatch console , or in the terminal with serverless logs:

serverless logs -f <function-name>
 
# Tail logs:
serverless logs -f <function-name> --tail

Bref Cloud

In the Bref Cloud  dashboard, click the request ID next to a log line to see all the logs of that request. The X-Ray trace of a request also shows its logs:

From the terminal, search for the request ID with bref logs. Its first 8 characters are enough, like in the dashboard:

bref logs --env=prod --search=8f507cfc --all

Serverless CLI

In CloudWatch Logs Insights, select the log group of the function and filter on the @requestId field:

fields @timestamp, @message
| filter @requestId = '8f507cfc-8b35-4e7e-9f26-f2a3a6e7e1a2'
| sort @timestamp asc