How to Handle Exceptions in PHP

Proper exception handling prevents silent failures and makes debugging much easier.

Step 1 — Basic try / catch / finally

try {
    $result = riskyOperation();
} catch (InvalidArgumentException $e) {
    // handle specific exception
    echo "Invalid input: " . $e->getMessage();
} catch (RuntimeException $e) {
    // handle broader category
    logger()->error($e->getMessage());
} finally {
    // always runs, even if an exception was thrown
    closeConnection();
}

Step 2 — Create Custom Exception Classes

class PaymentFailedException extends RuntimeException
{
    public function __construct(
        string $message,
        private readonly string $transactionId,
        int $code = 0,
        ?\Throwable $previous = null
    ) {
        parent::__construct($message, $code, $previous);
    }

    public function getTransactionId(): string
    {
        return $this->transactionId;
    }
}

// Throw it
throw new PaymentFailedException(
    message: 'Card declined',
    transactionId: 'txn_abc123',
    code: 402
);

Step 3 — Global Exception Handler

set_exception_handler(function (\Throwable $e) {
    error_log($e->getMessage() . " in " . $e->getFile() . ":" . $e->getLine());
    http_response_code(500);
    echo json_encode(['error' => 'An unexpected error occurred.']);
    exit(1);
});