The published limits are a ceiling, not a target

Google and Microsoft set sending limits to protect their systems from spam and from hacked accounts. The limits describe the most a mailbox may ever send in normal use. They do not say that sending that much is safe. A mailbox that sends hundreds of similar messages to people it has never written to before looks like spam or a compromised account to the provider, whether or not it is under the limit.

Microsoft states that Exchange Online, the email service in Microsoft 365, does not support bulk email. Google sets its limits to keep systems healthy and accounts safe, and accounts that send spam can be permanently restricted from sending.

Your mailbox can be blocked well below the limit

Both providers check sending behaviour, not only volume. Microsoft 365 has outbound spam policies that block a user from sending when the user exceeds sending limits or shows signs of sending spam. The user is placed on a list of restricted users and can only send again when an administrator removes the block. Google blocks new messages for up to 24 hours when a user reaches a sending limit, and can suspend the account.

Outreach is exactly the pattern these systems are built to catch: many messages, similar content, recipients who do not know the sender. In practice, mailboxes used for outreach are often restricted at volumes far lower than the published limits.

Spam complaints damage your whole domain

When recipients mark your email as spam, the complaints count against your domain, not only against the mailbox that sent it. Gmail tracks the spam rate for each sending domain. Google recommends keeping the rate below 0.1% and never reaching 0.3%, which is 3 complaints per 1,000 messages. Senders above that level lose access to Google’s help with delivery problems.

Cold outreach naturally gets more complaints than email to people who expect it. If you send outreach from the same domain as your everyday email, a high spam rate can push your quotes, invoices and replies to customers into the spam folder as well.

The numbers, for reference

As published in October 2026, Google Workspace allows about 2,000 messages per user per day on a paid account and 500 on a trial account. Microsoft 365 allows each mailbox to send to about 10,000 recipients per day, with a shared limit for external recipients across the whole organisation. Both providers change their limits from time to time, and the current figures are in their admin documentation. A mailbox used for outreach is likely to run into problems long before it reaches these numbers.

How LeadJabber avoids the problem

LeadJabber does not send your outreach from your Google Workspace or Microsoft 365 mailbox. It sends through your own SendGrid or Mailgun account on a dedicated IP address. Email gateways are built for sending in volume, so the mailbox limits and outbound spam blocks described here do not apply to your outreach. Your mailbox is only used as your sender identity and to collect replies into the Engager. See Why LeadJabber sends through an email gateway instead of your mailbox.

Email gateways are built for volume, not for spam

SendGrid and Mailgun are built to send large volumes of email reliably. They are not a way around spam rules. Each has an acceptable use policy that every sender must follow, and accounts that break it can be suspended. You own your SendGrid or Mailgun account, so you are responsible for following its policy. Send only to relevant recipients, keep complaints low and honour every unsubscribe. See Manage your unsubscribe list. Read the Twilio SendGrid Email Policy and the Mailgun Acceptable Use Policy before you start sending.