For real? A million emails at once?
If you're asking this question, you probably don't know enough to send email to a million recipients with any degree of reliability. Which one million recipients do you want to send to? Have they explicitly opted in to receive your email communications? If not, consider yourself a spammer. Anti-spam companies and projects will hunt you down and make your life miserable.
What's a better approach? Ask a different question. Ask: How can I satisfy my business goal of communicating with a profitable audience via email? The answer to that question is to carefully curate a list of customers and prospects who clearly want to receive your valuable communications. And then, follow best practices in communicating with them.
If you follow this path, you will make much more money from your efforts, and the list of providers willing to help you send that email will be very long indeed.
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