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Email best practices

Tips to prevent users from unsubscribing or marking emails as spam

Use the email best practices below to encourage a more positive user experience and a healthier sender reputation.

User engagement is of the biggest factors for ISPs when determining your sender reputation, which is critical for successful email delivery and inboxing. Positive engagement, such as opens and stars, can help improve your reputation, while negative engagement, like marking as spam, can hurt your sender reputation.


Always comply with CAN-SPAM and CASL for marketing emails.

Audience selection

  • Before importing and targeting users in Leanplum, consider running them through an email validation service.
  • Target users who have:
    • Opted-in to receive promotional type emails.
    • Engaged or opened an email in the last 6 months (or a length of time you determine). Users who are less engaged are more likely to engage negatively.
  • Set user expectations during sign up by letting them know:
    • The type of promotions they’ll be receiving.
    • The frequency in which they will receive the emails.
  • Avoid targeting users with addresses from affiliate vendors or were purchased. These users did not explicitly opt-in.
  • Increase sending volume by ramping up gradually, using our warmup schedule when introducing a new segment.
  • Target users who have not engaged in more than 6 months, once a quarter, or twice a year. Then permanently sunset this population. They may be negatively affecting your sending reputation and hindering your engaged population from receiving your campaigns.


  • Be sure to use your Leanplum requested sending domain.
  • Target users with subject lines, preheaders, and content that are relevant to their segment.
  • Include an unsubscribe link in all emails with marketing categories.
  • Ensure content encourages positive vs. negative recipient engagement.

    Positive Engagement

    • Moving from the Spam folder to the Inbox
    • Opens
    • Clicks
    • Reply to
    • Starring
    • Foldering
    • Labeling
    • Getting added to the address book

    Negative Engagement

    • Marking as spam
    • Unsubscribing
    • Not opening
    • Auto filtering to the spam folder
    • Moving mail straight to trash
    • Mark as not important


  • Analyze engagement metrics12 to 24 hours after each mailing and adjust targeting, content and mailings frequency for future sends if needed.

Sending volume

Inbox Providers monitor your messages across a 30-day rolling period looking for anomalies such as sudden volume spikes, as well as long breaks without any mailings. If you want to keep a certain sending volume we recommend not going beyond 30 days without sending.

Updated 3 months ago

Email best practices

Tips to prevent users from unsubscribing or marking emails as spam

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