Improving email deliverability
To optimize message deliverability with Nylas, it's important to have a few selective touches rather than sending thousands of emails per day from an account.
Nylas recommends doing the following to improve your email deliverability:
- When you send many messages in a group, space them out. Send them at most once every 30 seconds.
- If a message doesn't get through (for example, when the Nylas API returns a 429 error code), wait before retrying. If it fails again, use an exponential backoff to prevent the account from being flagged or rate-limited.
- Don't send more than the recommended 700 messages per day from a single account. Some providers lock out the user's account if it sends too many messages a day. For information on message limits by provider, see the Provider rate limits.
For information on how Exchange throttling works behind the scenes, refer to Understanding client throttling policies by Microsoft.
Unsolicited messages are more likely to raise flags compared to emailing an address you already have an email history with. Check out Mailchimp's guide for common spam filter triggers.
Microsoft Outlook has a rigid filter system and a reputation system. If a specific email address sends a lot of emails but doesn't get any replies, its reputation score decreases and it is eventually tagged as a spam/junk sender. To avoid this, have the recipients add the email address as a safe sender or as part of a safe mailing list. If emails are still tagged as spam/junk after a recipient marks them as safe, you might have a synchronization issue that can be solved by changing the account's password.
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