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

# Overview

Transformers are the data manipulation layer in Alumio. They define how data is reshaped, enriched, filtered, or mapped as it moves through an integration. Instead of writing custom code, you configure transformers through the Alumio interface to handle everything from simple field mappings to complex data restructuring.

Navigate to **Transformers** in the top navigation to create and manage transformers.

### What Transformers do

A transformer takes an input –– the entity data at a given point in the integration flow –– and produces a modified output. That output is then passed to the next step in the flow. Transformers can:

* Map fields from one structure to another (e.g. rename, move, or combine fields).
* Filter out records that do not meet a condition.
* Enrich data by pulling in values from Storages or other sources.
* Convert data types and formats.
* Execute logic conditionally based on the content of the data.
* Send emails, write to Storages, or interact with external systems as part of the data flow.

### Where Transformers are used

Transformers can be applied at multiple points in an integration flow:

| Location               | What it affects                                                                                |
| :--------------------- | :--------------------------------------------------------------------------------------------- |
| Incoming configuration | Transforms data after it is fetched from the source, before tasks are created.                 |
| Route                  | Transforms data between the Incoming and Outgoing steps.                                       |
| Outgoing configuration | Transforms data before it is sent to the destination system.                                   |
| HTTP Proxies           | Transforms the request before forwarding and the response before returning it to the consumer. |
| Email Transformer      | Sends an email at any point in the flow as part of data processing.                            |

### How Transformers work

Transformers are built by combining individual data transformers into a sequence. Each transformer in the sequence receives the output of the previous one, allowing you to chain multiple operations together into a single processing pipeline.

Transformers reference data using **placeholder syntax**, for example `&{fieldName}`, which allows you to dynamically reference values from the entity data anywhere in your transformer configuration.

Transformers are reusable. A single transformer configuration can be linked to multiple Incoming configurations, Routes, or Outgoing configurations, meaning changes made in one place apply everywhere it is used.