---
title: "Add a field"
description: "Add a field."
canonical: "https://grid82.com/docs/builder-api/fields/create"
updated: "2026-11-13"
---

# Add a field

`POST https://studio.grid82.app/v1/apps/{appId}/tables/{tableId}/fields`

Add a field.

Omit `id`; the platform returns an opaque `fld_…`. `config` is type-specific; keys for another type fail validation. Read `fields.types` for config shapes. Computed fields (lookup, rollup, formula, button) have no column and are derived at read time. A `link` creates its mirror on the other table in the same write; both are deleted together.

Requires the `schema:write` scope. Operation `fields.create`. MCP tool `fields_create`. CLI: `grid82 fields create` (`npx grid82`).

## Path parameters

| Name      | Type   | Required | Description |
| --------- | ------ | -------- | ----------- |
| `appId`   | string | yes      |             |
| `tableId` | string | yes      |             |

## Headers

| Name              | Type   | Required | Description                                                                                                                                                                                                                                                        |
| ----------------- | ------ | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `Idempotency-Key` | string | no       | Any unique string. Sending the same key with the same request again returns the first response (marked `Idempotency-Replayed: true`) instead of running it twice. Reusing it for a different request is refused with 409. Kept for 24 hours. Up to 255 characters. |

## Request body

A object.

**Authorizations**

- `Authorization` (bearer, in header, required)

## Response

**201**: Success

- `data` (`object`, required)
- `data.id` (`string`, required, pattern: `^[a-z][a-z0-9_]{0,62}$`)
- `data.name` (`string`, required, length: `1–120 chars`)
- `data.width` (`integer`, range: `60–900`)
- `data.type` (`string`, required)
- `data.config` (`object`, required, default: `{}`)

```json
{
  "data": {
    "id": "<string>",
    "name": "<string>",
    "width": 123,
    "type": "<string>",
    "config": {}
  }
}
```

**4XX**: Refused

- `error` (`object`, required)
- `error.code` (`enum<string>`, required, one of: `not_found, forbidden, unauthenticated, validation_failed, conflict, rate_limited, payment_required, not_implemented, internal`)
- `error.message` (`string`, required)
- `error.details` (`Record<string, unknown>`)

```json
{
  "error": {
    "code": "not_found",
    "message": "<string>",
    "details": {}
  }
}
```

**Example request**

```bash
curl --request POST \
  --url 'https://studio.grid82.app/v1/apps/<appId>/tables/<tableId>/fields' \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "name": "<string>",
  "type": "<string>"
}'
```