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How should CRM email reach an email service without rewriting every place that sends mail?

· 2 min read
Jon-Michael Lastimosa
Jon-Michael Lastimosa
Senior Web Developer

The question: campaigns should be able to go out through SendGrid, Mailgun, Postmark, Brevo or Amazon SES, and marketing email should come from a different address than confirmations and replies. Where does that switch live?

Context​

Four places in the CRM send mail (the campaign sender, confirmation and welcome emails, one-to-one email, and case replies), and every one of them calls wp_mail(). That is deliberate: the Mailer extension and any SMTP plugin govern the site's mail through it, and the campaign previewer relies on the sender going through one known path.

Options considered​

Give each sending path its own service code. Four copies of "if a service is set, call its API", which would drift, and every future sender (automations, digests) would need a fifth.

Take over all of the site's mail. A global pre_wp_mail hook would also catch WooCommerce receipts, password resets and form notifications, which the CRM has no business rerouting.

Wrap the CRM's own calls (chosen). Each CRM path calls FW_CRM_Senders::begin( 'marketing' | 'transactional' ) before wp_mail() and end() after. Only while that scope is open do the CRM's filters set the From name and address, add the Reply-To and, when the sender uses a service, answer pre_wp_mail by sending through the service's API.

Decision​

Sender profiles and email services act only inside a begin/end scope around the CRM's own wp_mail() calls. A failure from a service is reported through wp_mail_failed, the same signal wp_mail() gives, so every caller's existing error handling works unchanged. A service that is not set up, or cannot carry an attachment, leaves the email to the site's own mail.

Why​

The sending code stays exactly as it was, so the preview still matches the real email and nothing the site sends outside the CRM is touched. A new sending path only has to open the scope to get senders and services.

Status: Accepted (CRM 1.0.73).