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Testing & Optimization

Seed List

A set of test email addresses used to monitor inbox placement and email rendering across different providers.

Definition

A seed list is a collection of test email addresses used to verify email delivery and rendering. Marketers include seed addresses in their sends to check inbox placement (did it reach inbox or spam?) across different email providers and to preview how emails render in various clients. Seed lists are essential for deliverability monitoring.

Why It Matters

Without seed list testing, you cannot know if your emails are reaching the inbox or landing in spam. Different providers may treat your emails differently. Seed testing reveals deliverability issues before they affect your entire campaign and helps you catch rendering problems across email clients.

How It Works

You maintain email addresses at major providers (Gmail, Outlook, Yahoo, etc.) or use a deliverability service with seed addresses. Include these in your campaign sends. After sending, check each seed inbox to verify placement. Deliverability tools automate this process and provide reports.

Best Practices

  • 1Include seed addresses representing major email providers
  • 2Test regularly, especially when changing sending practices
  • 3Use automated seed testing tools for consistency
  • 4Check both inbox placement and spam folder
  • 5Monitor trends over time, not just individual campaigns

Frequently Asked Questions

At minimum, have seeds at Gmail, Outlook/Hotmail, Yahoo, and any providers significant in your audience. Deliverability services offer larger seed networks (50-100+ addresses) for comprehensive testing. More seeds mean better visibility.

They are indicative but not exact. Your actual subscribers may see different results based on their engagement history with you. Seeds provide a baseline view of deliverability; actual performance varies by recipient.