---
title: "List the JSON metadata fields measurements in a scope carry"
method: GET
path: "/cell_measurements/metadata_fields"
tags: ["Cell Measurements"]
---

# List the JSON metadata fields measurements in a scope carry

`GET /cell_measurements/metadata_fields`

## Request

- Base URL: `https://api.ionworks.com`
- URL: `https://api.ionworks.com/cell_measurements/metadata_fields`
- Auth: none declared

List metadata leaves usable as `meta` filters on the matching list endpoint.

Pass exactly one scope. The project scope covers measurement, instance and
spec metadata; the spec scope measurement and instance metadata; the
instance scope measurement metadata only.

## Query parameters

- `project_id` string, uuid, nullable
- `cell_specification_id` string, uuid, nullable
- `cell_instance_id` string, uuid, nullable

## Response `200`

Successful Response

- MeasurementMetadataFieldsResponse
  - `fields` MeasurementMetadataField[], required
    - `source` string, required: Which JSON it lives in, e.g. `test_setup`, `instance`, `spec_anode`. Used verbatim as the `<source>` of a `meta` filter.
    - `path` string, required: Dot-separated key path, e.g. `anode.loading`.
    - `kind` 'number' | 'text', required
    - `quantity` boolean, required: True when the leaf is a `{value, unit}` object; filter on `<path>.value` then.
    - `unit` string, nullable: Most common unit across rows, for Quantities.
    - `mixed_units` boolean: Rows disagree on the unit; values are not converted.
    - `count` integer, required: Number of measurements in scope carrying it.
    - `min` number, nullable: Smallest value, for number fields.
    - `max` number, nullable: Largest value, for number fields.
    - `decimals` integer, nullable: Fractional digits to display, the most any value stores (max 4).
    - `histogram` integer[], nullable: Counts in equal-width bars from `min` to `max`, for number fields.

## Other responses

- `422`: Validation Error

## Changes

- **2026-10-06** `6fbec094b30e`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/ionworks/apis/ionworks-api/changes/cell_measurements/metadata_fields/get.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)