---
title: "Email Merge Tags: Preview, Validate, and Export Without Surprises"
description: "Unresolved variables ruin sends quietly. Preview with datasets, let preflight catch gaps, then export in the syntax your ESP expects."
canonical: "https://memo.ly/blog/email-merge-tags-preview-validate-export"
updated: "2026-07-31"
---

# Email Merge Tags: Preview, Validate, and Export Without Surprises

Unresolved variables ruin sends quietly. Preview with datasets, let preflight catch gaps, then export in the syntax your ESP expects.

*Guide · 8 min read · Updated 2026-07-31*

The worst merge-tag failures look fine in the builder: `{{first_name}}` renders in preview, but production data exposes empty cells, wrong syntax, or a variable your ESP renamed three years ago.

## Preview with intentional data

Use [preview datasets](https://memo.ly/docs/understand-preview-datasets-and-variables.md) that stress edge cases - missing optional fields, long names, unicode - not only happy-path Jane Doe rows.

## Let preflight catch unresolved placeholders

Preflight variable rules flag placeholders that will not resolve at send time on the compiled HTML. Fix in the editor; do not ask reviewers to grep for curly braces.

## Export with the right dialect

Handoff includes a merge syntax choice and manifest of expected variables. Match what Klaviyo, Mailchimp, or your stack expects before [export](https://memo.ly/docs/export-approved-email-output.md).

## FAQ

### What if my ESP uses different syntax?

Export using the dialect your platform documents. Converting mid-flight in the ESP editor reintroduces errors.

### Can preflight know my live CRM data?

No. It validates structure and unresolved placeholders against your template - not your production database.

### Where do I fix unresolved variables?

In the editor before re-running preflight. See help on resolving unresolved variables.

### Do merge tags belong in plain text too?

Yes when personalization carries through - plain text should stay coherent when variables resolve.

## Related
- [Understand preview datasets](https://memo.ly/docs/understand-preview-datasets-and-variables.md)

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