How many emails can I send per second per IP to Gmail, Yahoo and O365?

Determining how many emails you can send per second per IP to Gmail, Yahoo, and O365 is a multifaceted issue with no single, straightforward answer. While some sources reference specific numbers (e.g., 1-4 million per day, historical Hotmail limits), the consensus emphasizes that sender reputation, IP warming, engagement, and authentication are paramount. There isn't technically a hard limit, with some senders achieving millions of emails per day per IP. However, ISPs like Gmail, Yahoo, and Microsoft employ algorithms that dynamically adjust limits based on sender behavior and reputation. A gradual ramp-up of volume (IP warming), starting with a few hundred emails per day and consistently increasing, is advised to build a positive reputation. Monitoring bounce rates and engagement metrics is crucial, as poor list hygiene or low engagement can trigger spam filters. Moreover, suitable hardware and infrastructure are necessary for efficiently sending large volumes. Ultimately, prioritize building a strong sender reputation, implement proper authentication (SPF, DKIM, DMARC), maintain a clean email list, and focus on delivering relevant, engaging content to subscribers.

There is no fixed limit on the number of emails you can send per second per IP to Gmail, Yahoo, and O365. Instead, ISPs like Gmail, Yahoo and Microsoft use algorithms based on sender reputation, authentication, and engagement to determine acceptable sending volumes. Gradual IP warming, starting with a few hundred emails per day and increasing gradually, is crucial for building a positive sender reputation. Maintaining a clean email list, monitoring bounce rates, and ensuring high engagement are essential. Exceeding thresholds, like sending over 5,000 emails to Gmail within a short time without proper authentication, can lead to deliverability issues. Sender reputation tools like Google Postmaster Tools and Microsoft SNDS are valuable for proactive monitoring. Sending relevant, personalized emails to engaged subscribers is more important than sending large volumes of unpersonalized messages.

Determining email sending limits to Gmail, Yahoo, and O365 is complex and highly dependent on sender reputation. While some sources mention specific numbers like 1-4 million emails per day per IP as a guideline or historical data point, it's crucial to understand that these are not hard limits. Throttling is largely reputation-driven, making a universal answer difficult. Successfully sending high volumes, like 20 million emails per day per IP, is possible with a good reputation, proper IP warming, and suitable hardware. Ultimately, the focus should be on building and maintaining a strong sender reputation and gradually increasing sending volume.

Gmail, Yahoo, and Microsoft Exchange Online all have sending limits in place to prevent spam, maintain system stability, and ensure service quality. These limits can depend on several factors, including the type of account, the user's license, and the recipient's domain. While specific sending rates are not always explicitly provided, focusing on email authentication (SPF, DKIM, DMARC) is crucial for improving deliverability and avoiding spam filters. Platforms like SparkPost offer tools to monitor and optimize throttle rates based on sender reputation.