I'm planning a project that heavily relies on sending emails, but I'm worried about the costs involved. To give you an idea, I could potentially be sending hundreds of millions of emails each month, with about 10,000 users sending emails to 10,000 subscribers each. Most email service providers charge around $1 for every 1,000 emails, which quickly adds up to around $100,000 monthly. Charging each user $10 just for one email monthly isn't realistic either, especially since some users could have as many as 1 million subscribers. I'm looking for alternatives but I don't want to dive into building my own SMTP server, as I've heard that it can lead to issues with being flagged as spam, among other challenges. What options do I have to tackle this problem?
3 Answers
You’re probably going to want to aggregate your emails instead of sending a separate email for each subscriber. If done right, you can significantly reduce the total number of emails and even think about batching them together. Also, is email the best medium for user updates? A web feed might be a more efficient way to handle this kind of communication without overwhelming your users' inboxes.
If you truly have 100 million users, I think there are bigger issues to address than just email costs! You might need to rethink your entire business strategy rather than just focusing on managing your email expenses. It’s all about getting your business model right first.
It sounds like you're dealing more with a business planning issue rather than a development one. Start small and utilize existing services for your initial phases. They’re usually affordable up to a certain limit, and you can scale your way up as your user base grows. Also consider outsourcing some of the email handling – it could save money in the long run due to their expertise and ability to manage email deliverability better.

Yeah, starting at a smaller scale and then transitioning to your in-house setup when you have more users and cash flow is the way to go. Don’t rush right into building everything yourself!