What’s the difference between preview and live testing?

Preview mode displays email content without sending:

Shows how merge fields will populate. Displays dynamic content based on test data. Reveals rendering issues in template preview. Does not test actual sending infrastructure.

Live testing sends real emails through production systems:

Validates trigger mechanisms actually fire. Confirms emails deliver through your ESP. Tests timing, delays, and conditions in real operation. Reveals issues preview mode cannot catch.

What live testing catches:

Trigger configuration errors. Sending authentication issues. Deliverability problems. System integration failures. Timing discrepancies.

Best practice:

Use preview for rapid content iteration. Use live testing with seed lists for final validation. Both are necessary; neither alone is sufficient.

Preview shows what should happen. Live testing proves what does happen.