# event-type-unknown

The **[event type](/docs/eventsourcingdb/event-types)** that the request asks for has **neither events nor a schema**.

- **Route:** `read-event-type`
- **Description:** `event type is unknown: it has neither events nor a registered schema`
- **Details:** **`value`**, the event type as the request gave it.

## Why It Happens

The database knows an event type once an **event of that type has been written** or a **schema has been registered** for it, see **[Registering Event Schemas](/learn/tutorials/first-steps-with-eventsourcingdb/registering-event-schemas)**. Reading an event type that has neither is refused. A typical cause is a typo in the type, or a read of a type before its first event has been written.

To see which event types the database knows, list them with the route `read-event-types`, see **[Listing Event Types](/learn/tutorials/first-steps-with-eventsourcingdb/listing-event-types)**.

## How to Fix It

Check the type for typos against the list of event types. The same request **succeeds once an event of the type has been written** or a schema has been registered for it; until then, it fails the same way.

## Example

To read the event type `io.eventsourcingdb.library.book-borrowed` before any book has been borrowed, and without a schema for it, EventSourcingDB answers with this error:

```json
{
  "type": "error",
  "data": {
    "code": "https://docs.eventsourcingdb.io/errors/event-type-unknown",
    "description": "event type is unknown: it has neither events nor a registered schema",
    "details": {
      "value": "io.eventsourcingdb.library.book-borrowed"
    }
  }
}
```