> For the complete documentation index, see [llms.txt](https://ciusji.gitbook.io/luden/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ciusji.gitbook.io/luden/extending/luden-architecture.md).

# Luden Architecture

Luden is a standalone application that doesn't have any requirements such as an inner database or others. Simultaneously some features need Redis, but these features are optional.

<figure><img src="https://3772893841-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FMfQt2eTfNlkZBgnWOxuC%2Fuploads%2FCsGWdcaJGkAKSYJrNFY2%2Fimage.png?alt=media&amp;token=46f38ca7-038a-4acd-b69a-4dd94aa9ae87" alt=""><figcaption></figcaption></figure>

## Definitions

* **Event**: An incoming message as a JSON object. Message can be sent to Luden via API or JavaScript library.
* **Destination**: Usually a database, but can be a different type of service as well. The destination is a service that contains structured records and supports an INSERT-like statement. &#x20;
* **Table**: A table in DB or any other structure within the destination.
* **BatchHeader**: Describes a structure of batch: fields and types along with table name.

## Destination Modes

Luden's destination can be operated in two modes:

* Stream: Data (events) is being sent to a destination as soon as possible.
* Batch: Data is being written to local disk and sent to a destination in batches, once in N (configurable) minutes.

## Transformation and Mapping Step

In this step, all configured mappings are applied to a JSON object and as a result, BatchHeader is generated. Read about [JavaScript Transformation](/luden/features/javascript-transform.md) and [Schema and Mapping](/luden/configuration/configuration.md) configuration. After all mapping are applied, JSON is flattened, and all special characters and spaces in field names are replaced with underscores. Also values types recognition happens here, read about [Typecast](/luden/features/typecast.md).