using a commercial SMTP server is the best option to avoid blacklisting and reduce server load.

Google SMTP (Premier Account): While reliable, it has sending limits (around 2,000 emails/day), which may not be enough for your needs. It also offers less control over deliverability.

Commercial SMTP Servers: These are ideal for high-volume email sending. They offer better deliverability, security, and protect your IP from blacklisting. Some reliable options include:

SMTPmart: Great for high-volume senders with strong features and tracking. Amazon SES: Cost-effective and scalable, but requires setup. Mailgun: Known for good support and deliverability.