> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dittofeed.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Write Modes

> How Dittofeed writes data from its API layer to ClickHouse.

Dittofeed has three write modes, configurable with the `WRITE_MODE` environment variable. These modes determine how Dittofeed writes data from its API layer to ClickHouse.

* `ch-async` (default): This mode writes data to ClickHouse directly and asynchronously. Enables the following underlying settings in Dittofeed's ClickHouse client:

  * `async_insert`
  * `wait_for_async_insert`
  * `wait_end_of_query`

* `kafka`: This mode buffers data in Kafka before writing it to ClickHouse. This mode is useful when you have a high volume of data and want to avoid overwhelming ClickHouse. For more information, see the [Kafka Write Mode page](/deployment/self-hosted/write-modes/kafka).