---
title: "Preview a cell-spec mapping and its unit conversion"
method: POST
path: "/model_builders/preview_mapping"
tags: ["Model builders"]
---

# Preview a cell-spec mapping and its unit conversion

`POST /model_builders/preview_mapping`

## Request

- Base URL: `https://api.ionworks.com`
- URL: `https://api.ionworks.com/model_builders/preview_mapping`
- Auth: none declared

What each mapped path reads in a cell spec: its value there and converted.

## Request body

- PreviewMappingRequest: A mapping to read from one cell spec, to show its unit conversion.
  - `cell_spec_id` string, required
  - `mapping` object, required: Parameter name -> dotted path in the cell spec, as in a DirectEntry mapping, e.g. 'cathode.properties.thickness'.

## Response `200`

Successful Response

- object

## Other responses

- `422`: Validation Error

## Changes

- **2026-10-22** `39d84bb8875e`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/ionworks/apis/ionworks-api/changes/model_builders/preview_mapping/post.md)

---

[API](https://skmtc.dev/ionworks/apis/ionworks-api.md) - [All operations](https://skmtc.dev/ionworks/apis/ionworks-api/llms.txt) - [OpenAPI document](https://skmtc.dev/ionworks/apis/ionworks-api/revisions/abebbbc5f60a?raw)