Do I need multiple sending streams for marketing and transactional email?

Usually, yes—it’s a good idea to use separate sending streams for marketing and transactional email.

Why separate them?

• Deliverability protection: Marketing emails tend to get more complaints, unsubscribes, and lower engagement. If they share the same stream/domain reputation as transactional mail, a marketing issue can hurt password resets, receipts, and alerts.
• Different sending patterns: Transactional mail is typically event-driven and time-sensitive, while marketing is scheduled and campaign-based.
• Better analytics and control: Separate streams make it easier to track performance, spam complaints, bounces, and engagement by email type.
• Compliance and preferences: It’s easier to manage unsubscribe behavior and consent rules for marketing without affecting required transactional messages.

Typical setup

• Transactional stream: password resets, order confirmations, security alerts
• Marketing stream: newsletters, promotions, product announcements

Best practice

If your email platform supports it, separate them by:

• Sending stream / IP pool
• Subdomain (e.g., mail.example.com for transactional and news.example.com for marketing)
• Suppression lists / unsubscribe handling

When you might not need two

If you send very low volume and have minimal marketing mail, a single stream may be acceptable—but it’s still not ideal if reliability matters.

If you want, I can also suggest a recommended domain/IP setup for both streams.