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Variable types

Every template declares its variables, which you can read from GET /api/templates/{id}. There are three types.

string

Section titled “string”

A piece of text inserted where the variable sits.

{ "client": "ACME Corp", "date": "November 4, 2026", "total": "$205.00" }
  • Values are inserted as-is: format dates, amounts and numbers in your code.
  • If the variable declares maxLength, a longer value is rejected with VARIABLE_TOO_LONG.

boolean

Section titled “boolean”

Shows or hides part of the document — a discount row, a legal paragraph, a stamp.

{ "discount": true }

Send true or false. When omitted, the variable’s default applies.

object-list

Section titled “object-list”

A repeating block: invoice lines, agenda items, a table of results. Send an array of objects.

{
  "lines": [
    { "label": "A5 flyers", "price": "$85" },
    { "label": "A3 posters", "price": "$120" },
    { "label": "Business cards", "price": "$40" }
  ]
}

The variable declares the shape each item must have:

{
  "type": "object-list",
  "name": "lines",
  "maxItems": 4,
  "itemFields": [
    { "name": "label", "type": "string", "required": true, "maxLength": 24 },
    { "name": "price", "type": "string", "required": true, "maxLength": 10 }
  ]
}
Field Meaning
itemFields The keys each object accepts, with their own limits
maxItems How many rows the layout was designed to hold

Keep your array within maxItems: the template reserves room for that many rows.

Reading the declaration

Section titled “Reading the declaration”

A quick way to see what a template expects:

Terminal window
curl -s https://app.imprime.io/api/templates/$ID -H "x-api-key: $IMPRIME_API_KEY" \
  | jq '.variableData[] | { name, type, required, default }'
{ "name": "client",   "type": "string",      "required": false, "default": "ImprimeCorp" }
{ "name": "discount", "type": "boolean",     "required": false, "default": true }
{ "name": "lines",    "type": "object-list", "required": false, "default": [ ... ] }