Compare Payload

Outliny's Compare Payload feature helps you detect differences between two versions of input data used for rendering templates (Emails or PDFs).

This is useful for:

  • Verifying if dynamic content has changed before regenerating documents.
  • Auditing changes over time (e.g., invoice updates, contract version tracking).
  • Avoiding redundant API calls if the payload is identical.

What is a Compare Payload?

A Compare Payload request checks if two sets of template parameters would generate different outputs — without fully rendering the Email or PDF. Instead of producing a document, it compares the incoming variables against a previous version and tells you if there’s any difference.

Endpoint

POST /api/v1/compare/payload

Authentication

Just like all other API calls, you must include your API Key:

Authorization: Bearer YOUR_API_KEY

Request Body

FieldTypeRequiredDescription
template_idstringYesThe ID of the template you're comparing against.
old_parametersobjectYesThe original parameters used previously.
new_parametersstringobjectThe new parameters you want to compare.

Example Request

POST https://api.outliny.com/api/v1/compare/payload
Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

{
  "template_id": "template_abc123",
  "old_parameters": {
    "customer_name": "Alice Johnson",
    "invoice_total": "$500"
  },
  "new_parameters": {
    "customer_name": "Alice Johnson",
    "invoice_total": "$500"
  }
}

Response

Fields returned:

  • status (string): "success"
  • is_different (boolean): true if payloads differ, false if identical
  • differences (object): fields that changed, if any

Example Response (Identical)

{
       "status": "success",
       "is_different": false,
       "differences": {}
}

Example Response (Differences Found)

{
  "status": "success",
  "is_different": true,
  "differences": {
    "invoice_total": {
      "old": "$500",
      "new": "$550"
    }
  }
}

When to Use Compare Payload

  • Efficiency: Only regenerate PDFs or Emails when data has actually changed.
  • Auditing: Track small but critical updates in contracts, invoices, HR letters, etc.
  • Versioning: Decide when to store or archive updated document versions.
  • Optimization: Save API credits and system processing by skipping unnecessary rendering.

Important Notes

  • Compare Payload only compares input parameters, not full rendered outputs.
  • Deep object comparison is supported (nested data structures too).
  • Only available for templates that use Jinja variables for dynamic content.
  • Fields not used in the template are ignored automatically for comparison.

Start Using Compare Payload!

Check the Full API Reference