---
title: "Preview an email template patch"
method: POST
path: "/public/v1/email-templates/{templateId}/patch-preview"
tags: ["Email Templates"]
---

# Preview an email template patch

`POST /public/v1/email-templates/{templateId}/patch-preview`

Returns the block-level before/after result of a patch without persisting it.

## Path parameters

- `templateId` integer, required

## Request body

- object
  - `expectedVersion` integer
  - `operations` union[], required
    - union
      - object
        - `op` 'SET_NAME', required
        - `name` string, required
      - object
        - `op` 'SET_SUBJECT', required
        - `subject` string, required
      - object
        - `op` 'REPLACE_BLOCK', required
        - `blockId` string, required
        - `block` object, required
      - object
        - `op` 'INSERT_BLOCK_AFTER', required
        - `afterBlockId` string, nullable, required
        - `block` object, required
      - object
        - `op` 'DELETE_BLOCK', required
        - `blockId` string, required
      - object
        - `op` 'REPLACE_DOCUMENT', required
        - `document` object, nullable

## Response `200`

Patch preview

- object
  - `templateId` number, required
  - `currentVersion` number, required
  - `name` object, required
    - `before` string, required
    - `after` string, required
    - `changed` boolean, required
  - `subject` object, required
    - `before` string, required
    - `after` string, required
    - `changed` boolean, required
  - `blockChanges` object[], required
    - `blockId` string, required
    - `changeType` 'ADDED' | 'REMOVED' | 'MODIFIED' | 'UNCHANGED', required
    - `before` object, nullable, required
      - `html` string, required
      - `text` string, required
    - `after` object, nullable, required
      - `html` string, required
      - `text` string, required
  - `resultDocument` object, nullable
  - `resultHtml` string, required
  - `resultText` string, required
  - `resultContentHash` string, required

## Other responses

- `400` — Invalid request
- `401` — Unauthorized
- `404` — Email template not found
- `409` — Version conflict (TEMPLATE_VERSION_CONFLICT)

## Changes

- **2026-10-03** `666cd9efa9f3` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/getfrontline/apis/public-api/changes/public/v1/email-templates/:templateId/patch-preview/post.md)

---

[API](https://skmtc.dev/getfrontline/apis/public-api.md) · [All operations](https://skmtc.dev/getfrontline/apis/public-api/llms.txt) · [OpenAPI document](https://skmtc.dev/getfrontline/apis/public-api/revisions/666cd9efa9f3?raw)