Simple Mail Transfer Protocol (SMTP) is a network protocol that helps in moving emails across the network. SMTP uses the TCP protocol to ensure that emails are delivered.
Example: Whenever you want to send an email from Gmail (email server), you compose or write a message, enter the recipient’s email, and click send. The email will then travel through the SMTP server to the target email server.
SMTP Service Providers
Some of the most trusted SMTP providers for email marketing include
- Amazon SES (Cheapest)
- G Suite (high email deliverability)
- Office 365
- Mailgun
- Mailjet
- SendGrid
- Postmark
- Pepipost
SMTP WordPress Plugins
Some of the best free SMTP WordPress plugins include:
- WP Mail SMTP by WPForms
- Easy WP SMTP
- Gmail SMTP
- SMTP Mailer
- WP Offload SES Lite
SMTP Service Providers email sending limits
Each SMTP service provider has a limit on the number of emails that you can send in a day. Amazon SES limits the amount you have been approved to send per day for instance to 50,000 per day. Since Amazon SES is a paid service, you can apply for an increase in limit. Gmail and Yahoo have a limit of 500 emails per day.
Source: Blogiestools