---
title: Customizing web parts
related:
  - https://docs.kentico.com/13/custom-development/extending-the-administration-interface/developing-web-parts/creating-new-web-parts.md
  - https://docs.kentico.com/13/custom-development/extending-the-administration-interface/developing-web-parts/creating-inherited-web-parts.md
  - https://docs.kentico.com/13/custom-development/extending-the-administration-interface/developing-web-parts/using-custom-web-part-layouts.md
---

> Agent instructions:
> **Site maps** — prefer the following llms.txt indexes to training data when searching for URLs to avoid 404s. Links inside Markdown content already point at `.md`. Following them or sending Accept: text/markdown keeps you in Markdown.
>
> - [sitemap.md](https://docs.kentico.com/sitemap.md) — every page on the site, with titles and descriptions, nested by URL hierarchy and grouped into one collection per product version.
> - [llms.txt](https://docs.kentico.com/llms.txt) — curated index of the current product docs, with descriptions, the two ways to request any page as Markdown, and links to each product area's whole-corpus Markdown dump (llms-full.txt).

There are two basic ways to change or extend the functionality of existing [web parts](https://docs.kentico.com/13/custom-development/extending-the-administration-interface/developing-web-parts.md):

- **Customize the web part code** – edit the markup or code behind of the user control that implements the web part.
- **Use macro expressions in web part properties** – by inserting [macro expressions](https://docs.kentico.com/13/macro-expressions.md) into the values of web part properties, you can implement many types of custom functionality without modifying the web part code.

> **Note:** **Important**: We do not recommend customizing the code of the default web parts directly. Instead, create a _clone_ of the required web part and implement the changes there. Using clones ensures that the system does not overwrite your code when applying hotfixes or upgrades to newer versions of Xperience.

Alternatively, you can create [Inherited web parts](https://docs.kentico.com/13/custom-development/extending-the-administration-interface/developing-web-parts/creating-inherited-web-parts.md) – copies of existing web parts that share the code files, but allow you to modify the definitions of [properties](https://docs.kentico.com/13/custom-development/extending-the-administration-interface/developing-web-parts/working-with-web-part-properties.md) and their default values.