If you send a marketing email to a customer, can you find out when the customer opens the email and view the content? Is this reasonable? What is the principle? -

As a foreign trade company, we need to regularly send some marketing emails to our customers, about several thousand in batches. A few days ago, I attended a training session where sales people sold their foreign trade software to us. One of the features was to send development emails to customers. The advantages described in this article are as follows: 1. the email format is HTML .., so the mail is small and not easily blocked; 2. you do not need to send the email address of the company domain name to avoid the risk of the Company domain name being blacklisted; 3. this is the most eye-catching. When the customer does not send a read receipt, he can find out when the customer checked the email. We are a foreign trade company, you need to send marketing emails to customers on a regular basis, which may contain several thousand in batches. A few days ago, I attended a training session where sales people sold their foreign trade software to us. One of the features was to send development emails to customers. The advantages described in this article are as follows: 1. the email format is HTML .., so the mail is small and not easily blocked; 2. you do not need to send the email address of the company domain name to avoid the risk of the Company domain name being blacklisted; 3. this is the most eye-catching. He can track when the customer has checked the email when the customer has not sent the read receipt! A series of product links are added to the sent emails, which can be tracked by the customer.
The question is, is this method reasonable? Will it be suspected of spying on the customer's privacy (like a Trojan )?
What is the principle of implementing these functions? Reply content: Generally, You can embed an image in an email and the link of the image is a url in a specific format, including the recipient address and email ID of the email. Generally, the image is directly accessed, the returned result is a 1x1 blank image. When you receive and open the email, the email client or browser tries to open the image link and display it. Then, the server where the image link is located can record the time when the email was opened.
The link in the email is also in a specific format. If the recipient clicks this link in the email, the corresponding log record is generated on the server.
The actual url of the image contained in the following email contains the encoded sender, recipient, email ID, subject, and other information (this image is displayed as red X to facilitate image tagging ).
This is not privacy. Now gmail will help users cache images to the server, which is ineffective. Done .. It is a small image. "To track when the customer opened the email and checked some content", what is the significance of this? If the customer does not approve of your product, they will not return your email or will not give you an order, even if you know when the customer opened your email, and browsed some products, but the result may not be the customer's response. So what are you going to do next? Yes. Our company is engaged in email marketing. The principle is very simple. The mailbox contains images. Images of your website. You must request your server. Then count the image request and click. Note that the email cannot contain js Code.