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Create a PDF from a Template

Lumin templates are document templates that created and saved in the Lumin application. Templates contain placeholders (tags and fields) that you can fill with dynamic data to create customized documents.

Important notes

  • Tags and field names use object.field syntax (for example: Client.Name, Customer.Name).
  • Some attributes like signer_roles and signing_type are specific to Lumin Sign templates. These are used when a template will later be sent as a signature request.
  • The same template can be used in two ways: to generate a plain PDF document, or as input for creating a signature request via the signature endpoints.

Understanding Merge Tags and Form Fields​

Lumin templates use two types of placeholders that you can fill with dynamic data:

Merge Tags​

Merge tags are text placeholders embedded directly in the document content. They use the syntax [text-merge|req|sender|object.field] and are replaced with actual values during document generation.

Examples:

  • [text-merge|req|sender|Client.Name] → Replaced with "Acme Corp"
  • [text-merge|req|sender|Effective.Date] → Replaced with "2025-08-01"

Form Fields​

Form fields are interactive elements that users can fill out. They include various input types:

  • Text: Single-line text input
  • Checkbox: Boolean true/false values
  • Signature: Digital signature fields
  • Radio Button: Single selection from multiple options

When generating a document from a template, the data you provide will be prefilled into the corresponding form fields.

Examples:

  • Customer.Name → Text field for customer name
  • Customer.AgreeToTerms → Checkbox for agreement
  • Customer.Signature → Signature field

Step 1: List available templates​

📖 API Reference: GET /templates

GET /v1/templates
Authorization: X-API-KEY
Accept: application/json

Response

{
  "page": 1,
  "limit": 25,
  "total_count": 1,
  "data": [
    {
      "template_id": "sign_abc123",
      "name": "Mutual NDA",
      "signing_type": "ORDER",
      "signer_roles": [
        { "name": "Customer", "group": 1 }
      ],
      "tags": [
        { "name": "Client.Name", "type": "merge_tag", "is_required": true },
        { "name": "Effective.Date", "type": "merge_tag", "is_required": false }
      ],
      "fields": [
        { "name": "Customer.Name", "type": "text", "is_required": true },
        { "name": "Customer.AgreeToTerms", "type": "checkbox", "is_required": true }
      ],
      "created_at": 1748456885430,
      "updated_at": 1748456885430
    }
  ]
}

Step 2: Generate PDF from template​

📖 API Reference: POST /templates/template_id/generate-document

POST /v1/templates/{template_id}/generate-document
Authorization: X-API-KEY
Content-Type: application/json
Accept: application/json

To download the PDF directly, set Accept: application/pdf — the API returns a binary PDF file.

Request Body

Fill the template's tags and fields with your data:

Note: For form fields, only text and checkbox field types support data prefilling. Signature and radio button fields cannot be prefilled and will appear empty in the generated document.

{
  "tags": {
    "Client.Name": "Acme Corp",
    "Effective.Date": "2025-08-01"
  },
  "fields": {
    "Customer.Name": "John Doe",
    "Customer.AgreeToTerms": true
  },
  "document_name": "NDA_AcmeCorp"
}

Response (JSON)

{
  "document_name": "NDA_AcmeCorp",
  "signed_url": "https://files.luminpdf.com/download/nda-acmecorp-abc123.pdf",
  "expires_at": 1766726700
}

Response (PDF)

  • When Accept: application/pdf is used, the API returns the PDF binary stream directly.