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

# Fundamentals

- [API and client libraries](https://docs.search.io/developer-documentation/fundamentals/api-and-client-libraries.md)
- [Search UI widgets](https://docs.search.io/developer-documentation/fundamentals/search-ui-widgets.md): Search.io comes with a set of easy to integrate search widgets. Learn how to customize the widgets.
- [Search results widget](https://docs.search.io/developer-documentation/fundamentals/search-ui-widgets/search-results-widget.md)
- [Search input widget](https://docs.search.io/developer-documentation/fundamentals/search-ui-widgets/search-input-widget.md)
- [Takeover Search Input Widget](https://docs.search.io/developer-documentation/fundamentals/search-ui-widgets/takeover-search-input-widget.md)
- [Configuration Objects](https://docs.search.io/developer-documentation/fundamentals/search-ui-widgets/configuration-objects.md)
- [Pipelines](https://docs.search.io/developer-documentation/fundamentals/pipelines.md)
- [Steps](https://docs.search.io/developer-documentation/fundamentals/pipelines/steps.md)
- [Record Pipelines](https://docs.search.io/developer-documentation/fundamentals/pipelines/record-pipelines.md)
- [Query pipelines](https://docs.search.io/developer-documentation/fundamentals/pipelines/query-pipelines.md)
- [Fundamental steps](https://docs.search.io/developer-documentation/fundamentals/pipelines/fundamental-steps.md)
- [Variable manipulation](https://docs.search.io/developer-documentation/fundamentals/pipelines/variable-manipulation.md)