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Overview

Suppression Updates helps maintain your global email subscription list. You can use this feature to ensure that users who should not be contacted are restricted from receiving emails. This is essential for maintaining compliance and protecting your sender reputation. Suppression blocks promotional and marketing campaigns only. Campaigns tagged as transactional — sent from delivery channels or via Inform — still reach suppressed users. Bounce is the one exception: it blocks all campaign types, including transactional.

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Unsubscribe vs. Suppression

Unsubscribe and suppression are related but distinct concepts. Confusing the two can lead to incorrect suppression management and compliance risk. Unsubscribe is a user action. When a user unsubscribes, MoEngage sets the standard unsubscription attribute on their profile to True. This is one of several reasons a user can end up suppressed. Suppression is a platform-side outcome. MoEngage suppresses a user — that is, stops sending them non-transactional campaigns — when any of the following is true for their profile:

• Any of the BUC attributes (Bounce, Unsubscribe, or Complaint) is set to True
• Frequency Capping (FC) limits are reached
• Do Not Disturb (DND) settings apply
• The user has opted out of a Subscription Category
• Double Opt-In (DOI) is unconfirmed

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How Brands Manage Suppression

There is no single “suppression list” in MoEngage email. Suppression is determined by attributes on the user’s profile, which brands can update in two ways:

1. Data ecosystem updates — User Import or the Server-to-Server (S2S) Data API. These overwrite the relevant standard attributes directly but do not generate events. (Exception: updates made through the user’s profile page in the dashboard go through email APIs and do generate events.)
2. Email-based updates — the Suppression Management section in email settings, or the Resubscribe API, Subscription Category API, or Double Opt-In API. These update the corresponding standard attributes and generate events against the user’s profile, giving you a traceable record of the consent change.

If you need an audit trail of consent changes, use the email-based methods.

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Use Cases

• Migrate from legacy email marketing platforms or ESPs: Bulk import historical suppression lists (bounces/unsubscribes/spams) when moving to MoEngage to protect your sender reputation from day one.
• Automate SendGrid sync: Automatically propagate suppression updates to SendGrid to keep your non-transactional senders compliant without manual work. This applies only if you select SendGrid Tracking in Unsubscribe Settings while configuring an email sender in MoEngage.
• **Protect critical emails: **Maintain a global suppression list for marketing campaigns without blocking essential transactional alerts, such as one-time passwords (OTPs) or password resets.
• Manage suppression requests independently: Unsubscribe or resubscribe users in self-service enabled workspaces, eliminating the need to raise support tickets for individual status updates.

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Bulk Import of Users

A primary function of Suppression Updates is to import existing subscription lists in bulk. This is a critical step during email onboarding, especially when migrating from a previous email marketing platform or ESP. Use this feature to upload CSV lists of users who have previously:

• Experienced email bounces.
• Unsubscribed from your communications.
• Marked your emails as spam (complained).

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CSV File Requirements

To ensure your subscription list is imported correctly, your CSV file must follow these requirements:

• The CSV file must strictly follow the column sequence listed below. While column headers are case-insensitive, the sequence must not be altered to ensure successful processing.
  • Identifier column: Label this column Email ID, MoEngage ID, or Email ID/MoEngage ID. Note that if PII tokenization is enabled for your workspace, you must label this column ID.
  • Unsubscribe
  • Bounce
  • Spam
• For each user, the CSV should specify true or false (case-insensitive) for the columns: Unsubscribe, Bounce, and Spam. For example, a user who unsubscribed but never bounced or marked the email as spam would have the following values:
  • Unsubscribe: true
  • Bounce: false
  • Spam: false
• Your CSV file must not contain duplicate email entries. If duplicates are found, MoEngage processes only the last entry in the file and skips all preceding duplicates. 
• A user is considered resubscribed only when MoEngage updates their status from true (suppressed) to false (active) for all three suppression categories. If the user’s current status for all three entries is already false, no update is performed.
• A user becomes reachable if all three suppression categories are set to false, and the user is suppressed if any of the three categories is set to true.
• You can use the same CSV file to unsubscribe or resubscribe a user, depending on the value specified in the Unsubscribe column. To make a previously unsubscribed user reachable, upload a file with the Unsubscribe value set to false. If Bounce and Complaint are also false, the user is eligible to receive emails again.
• MoEngage generates the following events when the status of BUC attributes (Bounce, Unsubscribe, or Complaint) changes:

BUC attributes	Status Change	Generated Event Name
Bounce	False to True	Email Bounced
	True to False	Email Bounce Reset
Unsubscribe	False to True	Email Unsubscribed
	True to False	Email Resubscribed
Complaint	False to True	Email Complained
	True to False	Email Complain Reset

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Upload the Subscription Update File

• If self-serve for email onboarding is enabled for your workspace, you can manage the suppression as described here.
• If self-serve for email onboarding is not enabled for your workspace, you can manage the suppression as described here. 

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FUP Limits

To maintain system stability and prevent excessive load on the Suppression Management service, the following constraints are enforced at the workspace level:

• File size limit: Uploads are strictly limited to 75 MB per file.
• Duplicate file name validation: To avoid redundant processing, MoEngage checks for existing filenames. If a file with the same name has already been processed, the upload request is rejected.
• Limit upload frequency: To ensure equitable resource availability, file uploads are subject to the following frequency limits:

  Time Window	Maximum Allowed Uploads
  5 Minutes	5 uploads
  15 Minutes	10 uploads
  1 Hour	20 uploads
  24 Hours	50 uploads