Merge tags: personalizing email with subscriber data

How it works

You write a placeholder where the data should go. At send time, the email platform swaps it for that recipient's value. Each platform has its own syntax. Many, Mimeo included, use Liquid, with the placeholder in double curly braces:

Hi {{ person.first_name | default: "there" }},

Three pieces do most of the work:

• The placeholder names a piece of data: a first name, a plan, a city.
• A fallback covers people with no value. Without one, a missing first name reads "Hi ,".
• A condition shows different text to different people, such as one line for customers and another for everyone else.

Why it matters

• Relevance. A first name, the plan someone is on or the product they bought makes the email read as written for them.
• Mistakes are public. A broken or empty placeholder lands in front of every recipient, so fallbacks and previews matter.
• The data has to exist. A merge tag can only use what you've collected and kept clean.

How Mimeo handles it

Mimeo calls them person variables: {{ person.first_name }}, {{ person.last_name }}, {{ person.name }}, {{ person.email }}, {{ person.fields.<key> }} for any custom field you've declared under Settings → Fields, and person.tags, the person's tag names. The default filter gives each one a fallback, and {% if %}, {% unless %} and {% else %} give you conditionals: {% if person.tags contains "customer" %} shows a block only to people with that tag. Subject lines and pre-headers take person variables too.

Data reaches those variables through imports and events: the person object on each event sets names, fields and tags. Field keys must be declared first, or the API ignores them (fields). Layouts add {{ unsubscribe_url }} and {{ mailing_address }}, and renewal reminders get automation.subscription for the subscription behind that run.

The preview renders the real email for one actual person, with every variable resolved, so a blank shows up before anyone receives it. See Mimeo terms for emails in Mimeo's own words.