What problems can arise when creating a mailing service on shared?

Question

PHP

In my opinion, everything should be simple - cron runs a script at a certain interval that reads data from the database and sends the right emails to the right recipients at the right time, which were checked for spam, using mail ().
For some reason, the creator of this question seems to disagree with me:

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It also interests with the help of what php technologies you can send letters.
It is clear that the standard mail is not suitable for this.

Answer 1

Restrictions on memory, on accesses to a disk can prevent. They can block your account for mailing in large quantities (the fact that you check for spam will not bother anyone).

Answer 2

Use an external mailing service like mandrill (or mailchimp). They have large free limits, and you will automatically save yourself from problems: with delivery, with sending, with mail mechanisms in general.

Answer 3

It is better to use a specialized mailing service. As a rule, hosting companies set a limit on the number of emails sent per hour within 200 emails.