In magento 2 how can we login customer programatically using email and password?

Question

In magento 2 customer login programatically using email and password?

Answer 1

Try this

<?php

...

private $customer;
private $customerSession;

public function __construct(
    ...
    \Magento\Customer\Model\Customer $customer,
    \Magento\Customer\Model\Session $customerSession
) {
    $this->customer = $customer;
    $this->customerSession = $customerSession;
    ...
}

... 

$customerEmail = "[email protected]"; // add customer email address
$websiteId = "1"; // add your website id

$customer = $this->customer;
$customer->setWebsiteId($websiteId);
$customer->loadByEmail($customerEmail);

$this->customerSession->setCustomerAsLoggedIn($customer);

echo "customer is logged in";

Answer 2

protected $customer;
protected $customerSession;

public function __construct(...
    \Magento\Customer\Model\Customer $customer,
    \Magento\Customer\Model\Session $customerSession) {
    ...
    $this->customer = $customer;
    $this->customerSession = $customerSession;
    ...
}
...    
$customer = $this->customer->loadByEmail("[email protected]"); 
$this->customerSession->setCustomerAsLoggedIn($customer);

if($this->customerSession->isLoggedIn()) {
    echo "Customer Logged in";
}else{
    echo "customer is not Logged in";
}