What are common connection and message limits imposed by different email providers?

Email marketer from Email Marketing Forum mentions that Yahoo has stricter limits, especially for new senders. It's important to monitor deliverability and sender reputation closely to avoid being blocked. They suggest using a reputable email service provider (ESP) to manage sending volume and comply with Yahoo's guidelines.

Email marketer from Mailchimp explains that understanding sending limits is essential for successful email marketing campaigns. Mailchimp advises users to adhere to their platform's sending limits, monitor bounce rates, and warm up IP addresses to build a positive sending reputation and avoid restrictions.

Email marketer from Reddit shares that Gmail has limits of around 500 emails per day for free accounts and higher limits for paid Google Workspace accounts. Exceeding these limits can lead to temporary suspension.

Email marketer from SparkPost Blog explains that many ISPs implement connection throttling, limiting the number of simultaneous connections or messages per connection from a specific IP address. This is done to manage server load and prevent abuse. Senders should be aware of these limits and adjust their sending behavior accordingly.

Email marketer from Email Geeks explains that outside of Yahoo and their messages-per-connection limit, limits are seen a good bit at various european and chinese providers. The limiting of the number of concurrent connections from a given IP or IP block is bigger/more painful, especially when that number is very low and/or they have multiple domains that share MXs. Comcast is in that list, but Orange is the poster child.

Email marketer from Litmus explains that warming up new IP addresses is crucial to establishing a positive sender reputation. This involves gradually increasing sending volume over time, starting with small batches and monitoring engagement metrics. This helps ISPs learn that the sender is legitimate and reduces the risk of being blocked.

Email marketer from EmailOnAcid explains the importance of email authentication (SPF, DKIM, DMARC) to improve deliverability. Proper authentication signals to email providers that you are a legitimate sender, helping bypass spam filters and ensuring your emails reach the inbox. This also helps reduce risks with limitations

Email marketer from SendGrid shares that it's crucial to understand the sending limits imposed by different email providers. These limits help maintain deliverability and sender reputation. SendGrid recommends segmenting email lists and gradually increasing sending volume to avoid triggering spam filters and exceeding limits.

Email marketer from StackOverflow explains that to avoid rate limits, implement retry mechanisms with exponential backoff. Also, use bulk email sending services instead of trying to send directly from personal accounts. Check and respect the providers terms and conditions

Email marketer from Campaign Monitor shares that avoiding email sending limits and blocks can be achieved by authenticating your domain with SPF, DKIM, and DMARC. Also, monitor your sender score and IP reputation regularly to identify and fix any issues before they affect your email deliverability.

Expert from Spam Resource shares that Yahoo often imposes strict connection limits and may throttle connections from senders with lower reputations. These limits can fluctuate based on various factors, making consistent monitoring crucial.

Expert from Email Geeks shares that a lot of energy and effort is put into managing large volumes of legitimate outbound email.

Expert from Email Geeks explains that Yahoo used to have a limit of 5 messages per session, closing the connection after the RSET, and it was considered a significant improvement when they increased it to 20.

Expert from Word to the Wise explains that Microsoft's Hotmail/Outlook.com uses sophisticated algorithms to determine connection limits. These limits can be very restrictive, especially for new IPs or those with poor sending reputations, and often involve limiting the number of connections and messages per connection.

Expert from Email Geeks mentions that QQ has a limit of 1 connection per outbound IP, and there's an Italian provider with a similar limit. These limits apply to perfectly good mail, not just bad mail.

Documentation from RFC Editor specifies that while SMTP (RFC 5321) doesn't mandate specific message limits, it recommends that implementations consider reasonable limits to prevent abuse and resource exhaustion. These include limits on message size, number of recipients, and the number of messages sent per connection.

Documentation from AWS Documentation details Amazon SES sending limits. These include a maximum sending rate (emails per second) and a daily sending quota. These limits vary based on sender reputation and can be increased by requesting an increase through the AWS console.

Documentation from Microsoft Learn explains that Exchange Online has various sending limits to prevent spam and maintain service health. These include recipient rate limits (messages per minute), sending limits (messages per day), and message size limits. Specific limits vary depending on the subscription type and sender reputation.

Documentation from Google Workspace Admin Help details Gmail's sending limits, which are in place to combat spam and abuse. Limits are placed on the number of emails sent per day and the number of recipients per message. These limits depend on the Gmail version (e.g., free vs. paid Google Workspace) and the sender's reputation. Exceeding these limits can result in temporary account restrictions.

Documentation from Postmark highlights transactional email limits. It includes the sending rate for each transactional email type. For example, the initial limit is lower for marketing based transactional emails.