I want to send out a marketing email to a little over 11,000 email addrresses using Outlook 2007 (could also be 2010) on an account configured to use the SendGrid SMTP server. what is the limit to the number of email adresses I can put into the BCC field before sendgrid will start complaining? Can I put all of them in there, or do I need to process them in batches? How big can the batches be?

  • There is no psychical limits but the more you send the larger the memory used so can fail, use a distribution list, only business contact manager has a limit of 1000 Jun 13, 2014 at 9:16
  • What's the point? Just send 11000 individual emails. Jun 13, 2014 at 9:35
  • 11,000 individual mails without a tool? how do you suggest I do that in a timely fashion?
    – Nzall
    Jun 13, 2014 at 9:37
  • There is usually limits. I advise against this. Look up tarpitting. Nate, people send large mail shots over a period of time. For many good reasons. I've written mail shot software and dealt with it a lot, the point is if Server A receives X emails at once from you (although to different people), all with the same content, it could be seen as spam.
    – Dave
    Jun 13, 2014 at 9:46
  • You could also bring the server to a grinding halt, causing it to time out/crash and then not know which emails did send or didn't. In one company, we sent 10 emails per 10 minutes, some mail shots took a few weeks to send. Why do you need them all to get the email in a timely manner? If there is a limited promotion period, start it early or increase the promotional period. You also need to consider (off topic) if you send all at once, can you cope with the responses
    – Dave
    Jun 13, 2014 at 9:48

1 Answer 1


from sendgrids documentation

Customers should utilize SMTPAPI if this is an option. As with SMTP, 100 messages can be sent with each connection, but there can be 1000 recipients for each message.

reminding that the receiving end also has limits on how many mail addresses you can put on the to , cc and bcc fields

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