> ## Documentation Index
> Fetch the complete documentation index at: https://mage-staging.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Sources technical documentation

> A source is a system that you want to load data from and synchronize it into another system. A source can be a 3rd party API, SaaS, database, data warehouse, or a data lake.

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  <img alt="mage sources" src="https://github.com/mage-ai/assets/blob/main/mage-sources.png?raw=true" />
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## Singer spec

Mage uses the data engineering community standard for data integrations called the
[Singer spec](https://github.com/singer-io/getting-started/blob/master/docs/SPEC.md).

In addition,
Mage further standardizes the spec and provides common classes and methods to make implementing them easier and faster.

## Folder structure

Sources are defined in the `mage_integrations/sources/` directory.

All sources should be a subclass of the `Source` class defined in
`mage_integrations/sources/base.py`.