How can you safely test deliverability to specific ISPs?

Safe ISP-specific deliverability testing:

Seed account setup:

Create or maintain test accounts at major ISPs

Gmail, Outlook, Yahoo, iCloud at minimum

Use for consistent testing

Testing protocol:

Send identical content to all seeds

Check placement (inbox, spam, promotions)

Record results consistently

Volume considerations:

Test with production-like but small volume

Avoid mass testing that triggers rate limits

Space tests appropriately

Tools:

Third-party seed testing services

Panel data services

Manual verification

Regular testing provides baseline and detects changes.

Send scout ships to each port. Report back on reception before the fleet arrives.