What sort of gotchas/tips/hints can you share for a .Net program which will send possibly 10k+ emails a day to subscribers?

Question

I know how to write the basic c# code to send emails, but I'm wondering about any larger issues involved. Are there things I should avoid? Best practices? etc

Thanks!!

Answer 1

• Make sure you use a hosting service which will not disable your account because of the amount of email you send.
• Add some kind of audit or logging so you know what mails you have sent
• Use BCC to send the same mail to multiple recipients
• Queue the mail to avoid bursts of emails
• Consider sending mail in batches. E.g. you notify users of a new forum post, then don't send out a mail to everyone each time someone posts, offer the possiblity of daily digests.
• As others have pointed out, use threading to send a high amount of mail

Answer 2

You probably want to spawn this stuff out in batches, so everything is not being sent from one process in a continuous loop. You can do this much quicker if you group the batches by 25 e-mails and spawn say 50 threads to send those 25 queues. Given your 10,000 e-mails it would only take 8 loops to complete the whole batch of e-mails.

You can obviously change these numbers, but you will need to split this up in to multiple threads that send a group of e-mail. It will be up to you to find the optimal numbers of this process.