> For the complete documentation index, see [llms.txt](https://v2.dataos.info/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://v2.dataos.info/references/dataos-resources/nilus/concepts.md).

# Core concepts

These pages cover the foundational ideas behind Nilus that apply across all pipeline modes: how the runtime ingests and loads data, how it handles schema changes over time, how it resolves credentials, and how it protects sensitive fields. Read these before diving into connector pages or mode-specific config.

* [Architecture and Mechanism](/references/dataos-resources/nilus/concepts/architecture-and-mechanism.md)
* [Schema Evolution](/references/dataos-resources/nilus/concepts/schema-evolution.md)
* [Understanding Data Masking](/references/dataos-resources/nilus/concepts/understanding-data-masking.md)


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