# Attach a file to a board record

Declares a file against one record on a custom board and answers the row plus a signed upload url; the bytes go straight to storage in a second request and never through this service. WRITE access, not read — pinning a file changes the record. The pack-page twin is `post_definitions_key_rows_rowId_files`.

Access class: `board:write`.

## Endpoint

`POST /v1/boards/{id}/rows/{rowId}/files`

## Parameters

| Name | In | Type | Required |
| --- | --- | --- | --- |
| id | path | string | Yes |
| rowId | path | string | Yes |

## Request body

Content type: `application/json`.

```json
{
  "body": {
    "contentType": "string",
    "documentType": "string",
    "name": "string",
    "periodEnd": "string",
    "periodStart": "string",
    "sizeBytes": 1
  },
  "params": {
    ":id": "string",
    ":rowId": ""
  },
  "query": {}
}
```

## Responses

### 201

the action's answer

Content type: `application/json`.

```json
{}
```

### default

a refusal: `{"error": "<what a person needs to read>"}`. 401 no credential, 402 the plan does not include this, 403 the seat does not, 404 the thing does not exist or is not yours to see.

Content type: `application/json`.

```json
{
  "error": "string"
}
```