Is the mail merge preview free?

Yes. It's completely free with no sign-up and no contact limit.

Is my contact list uploaded anywhere?

No. Your CSV and template are parsed and merged entirely in your browser. Nothing is uploaded to a server.

What merge-tag format does it use?

It uses {{field}} tags that match your CSV column headers, for example {{first_name}} pulls from a first_name column. Tags that don't match a column are flagged as broken.

Can I set a fallback for empty fields?

Yes. You can set a default per field, so an empty first_name becomes 'there' (or whatever you choose) instead of leaving an awkward gap.

Does it check for spam words?

Yes. It runs a spam-trigger word check on each merged body and flags subject lines that are too long, so you can fix issues before sending.

Mail Merge Preview & Validator — Free Personalization Tester

Mail-Merge Preview & Validator

This free mail-merge preview tool renders every personalized email from your template and CSV so you can read them before sending. It flags broken {{merge tags}} that don't match a column, rows with empty fields, and CSV columns your template never uses, and lets you set fallbacks. Everything runs in your browser — your contact list is never uploaded.

Runs in your browser — your data stays on your device.

Subject template Body template

Contacts (CSV)

First row = column headers = your merge fields.

Fallbacks for empty fields (optional)

Contacts

Clean

With issues

Preview

Send these at scale

Once your merge looks clean, load the list into a sending platform to personalize and send across many inboxes — or pair it with a B2B database to source the contacts.

Send with Instantly Source contacts with Apollo Affiliate links · how this works

Answers

Mail-merge preview — your questions answered

Is the mail merge preview free?: Yes. It's completely free with no sign-up and no contact limit.

Is my contact list uploaded anywhere?: No. Your CSV and template are parsed and merged entirely in your browser. Nothing is uploaded to a server.

What merge-tag format does it use?: It uses {{field}} tags that match your CSV column headers, for example {{first_name}} pulls from a first_name column. Tags that don't match a column are flagged as broken.

Can I set a fallback for empty fields?: Yes. You can set a default per field, so an empty first_name becomes 'there' (or whatever you choose) instead of leaving an awkward gap.

Does it check for spam words?: Yes. It runs a spam-trigger word check on each merged body and flags subject lines that are too long, so you can fix issues before sending.

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