SMTP relay service providers are companies or organizations that offer services to handle the sending and delivery of email messages on behalf of their clients. These providers act as intermediaries between the sender and the recipient's email servers, ensuring that emails are successfully delivered and reducing the chances of them being marked as spam.
There are several SMTP relay service providers available in the market, each offering their own set of features and capabilities. Some popular providers include SMTPget, Digitalak,iDealsmtp, and SparkPost.
Source-https://smtpget.com/smtp-service-provider/
