# type-mismatch

<Badge variant="warning">400 Bad Request</Badge> <Badge variant="muted">type-mismatch</Badge>

| Field           | Value                                          |
|-----------------|------------------------------------------------|
| **Type URI**    | `https://docs.kordiam.app/docs/errors/type-mismatch` |
| **HTTP Status** | `400 Bad Request`                              |

## Description

A value in the request could not be converted to the expected type. This applies to query parameters, path variables, headers, and request body fields. For example, a string was provided where a number was expected, a number was provided where an object was expected, or a date value does not match the required format.

## Response Examples

### Parameter type mismatch

```json
{
  "type": "https://docs.kordiam.app/docs/errors/type-mismatch",
  "title": "Type Mismatch",
  "status": 400,
  "detail": "Parameter 'id' should be a number but received 'abc'",
  "instance": "/api/v2/platforms/abc",
  "traceId": "abc-123-def",
  "parameterName": "id",
  "expectedType": "a number",
  "actualValue": "abc"
}
```

### Request body type mismatch

When the mismatch occurs inside the JSON request body, the response includes an `errors` array with the field path:

```json
{
  "type": "https://docs.kordiam.app/docs/errors/type-mismatch",
  "title": "Type Mismatch",
  "status": 400,
  "detail": "Expected an object for 'user' but received a number",
  "instance": "/api/v2/elements",
  "traceId": "abc-123-def",
  "errors": [
    {
      "scope": "body",
      "path": "tasks[0].user",
      "code": "type-mismatch",
      "message": "Expected an object for 'user' but received a number"
    }
  ]
}
```

## Common Causes

- Passing a string value for a numeric parameter (e.g., `id=abc` instead of `id=42`)
- Using an invalid date format (e.g., `2026-13-01` or `01/01/2026` instead of `2026-01-01`)
- Supplying a non-boolean value for a boolean parameter (e.g., `active=yes` instead of `active=true`)
- Sending a primitive value (number, string) for a field that expects an object (e.g., `"user": 123` instead of `"user": {"id": 123}`)
- Sending a single value where an array is expected, or vice versa

## How to Fix

1. Check the expected type for each field or parameter in the API reference.
2. For parameter mismatches, read the `detail` field, which identifies the problematic parameter and the expected type.
3. For request body mismatches, inspect the `errors` array — each entry includes the `path` to the problematic field and a `message` describing the expected vs. actual type.