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Last updated: 2019-11-26

Works with CiviCRM 5.13 or higher.

FlexMailer is an email delivery system for CiviCRM. It does not define any user interface; rather, it replaces some internal parts of CiviMail and provides new APIs. Other extensions can use these APIs to provide more fine-grained control over email delivery.

A few example scenarios supported by FlexMailer:

  • Composition: Change how email messages are composed. CiviMail has built-in support for simple tokens. With FlexMailer, an extension can change this in deep ways, e.g.

    • Compose messages with Twig, Mustache, or some other language.
    • Improve the performance of Smarty-based mailings (by disabling CiviMail tokens).
  • Delivery: Instead of delivering email messages over SMTP one-at-a-time, deliver them using batched SMTP or batched web-service calls.
  • Tracking: Change the tracking codes used for click-throughs or opens.

For more detailed discussion, see