# data-missing

An event leaves out its **data**.

- **Route:** `write-events`
- **Description:** `data is missing: expected a JSON object`
- **Details:** **`event`**, the place of the event in its list, counting from 0.

## Why It Happens

Every event carries its payload in **`data`**, which is a **JSON object**, see **[CloudEvents](/docs/eventsourcingdb/cloud-events)**. The database reports this error when an event of a write **leaves out `data`**. An event that has nothing to say beyond its subject and type still needs `data`, as an empty object.

A typical cause is a serializer that **leaves out empty fields**, and with them the data of an event that has none. A `data` of `null`, or of another JSON type than an object, such as a string, does not get this far: the database rejects the request with **`400 Bad Request`**, see **[Requests](/docs/eventsourcingdb/api#requests)**.

## How to Fix It

Send `data` with every event, as `{}` where the event carries nothing, and make your serializer keep it. Sending the same request again fails the same way, since the error depends on the request alone.

## Example

For a write whose first event leaves out its data, EventSourcingDB answers with this error, as a line of the stream, and then ends the stream with its `end` item:

```json
{
  "type": "error",
  "data": {
    "code": "https://docs.eventsourcingdb.io/errors/data-missing",
    "description": "data is missing: expected a JSON object",
    "details": {
      "event": 0
    }
  }
}
```