It is generally not recommended to send a large number of cold emails all at once, as this can increase the risk of your emails being marked as spam and your domain being blacklisted.
The success of your cold emailing campaign also depends on the reputation of your domain. If your domain has a good reputation, you may be able to send more emails without being marked as spam. On the other hand, if your domain has a poor reputation, you may need to send fewer emails to avoid being marked as spam.
Instead of sending a large number of emails all at once, it is generally a good idea to start with a smaller volume of emails and gradually increase the volume over time.
This can help establish your domain as a legitimate sender and prevent your emails from being marked as spam.
It is also important to consider the rate limits imposed by email service providers when sending cold emails.
Most email service providers have limits on the number of emails that can be sent in a given period. For example, Google Workspace allows users to send up to 2,000 messages per day, while Outlook 365 allows users to send up to 30 messages per minute and Zoho Mail allows users to send up to 300 messages per hour. If you exceed these limits, your emails may not be delivered and you may risk having your domain blacklisted.
In general, it is a good idea to start with a small volume of cold emails and gradually increase the volume over time, while also considering the rate limits imposed by your email service provider and the reputation of your domain. This can help ensure that your emails are delivered and not marked as spam, and can help you effectively reach out to potential customers and clients.