---
title: Custom development
related:
  - https://docs.kentico.com/13/external-utilities/kentico-xperience-installation-manager.md
  - https://docs.kentico.com/13/developing-websites/troubleshooting-websites.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).

- [Best practices for customization](https://docs.kentico.com/13/custom-development/best-practices-for-customization.md)
- [Applying customizations in the Xperience environment](https://docs.kentico.com/13/custom-development/applying-customizations-in-the-xperience-environment.md)
- [Adding custom assemblies](https://docs.kentico.com/13/custom-development/adding-custom-assemblies.md)
- [Extending the administration interface](https://docs.kentico.com/13/custom-development/extending-the-administration-interface.md)
- [Creating custom modules](https://docs.kentico.com/13/custom-development/creating-custom-modules.md)
- [Handling global events](https://docs.kentico.com/13/custom-development/handling-global-events.md)
- [Customizing system classes](https://docs.kentico.com/13/custom-development/customizing-system-classes.md)
- [Database table API](https://docs.kentico.com/13/custom-development/database-table-api.md)
- [Customizing providers](https://docs.kentico.com/13/custom-development/customizing-providers.md)
- [Customizing the system's data classes (Info objects)](https://docs.kentico.com/13/custom-development/customizing-the-system-s-data-classes-info-objects.md)
- [Decorating system services](https://docs.kentico.com/13/custom-development/decorating-system-services.md)
- [Managing field data types](https://docs.kentico.com/13/custom-development/managing-field-data-types.md)
- [Retrieving database data using ObjectQuery API](https://docs.kentico.com/13/custom-development/retrieving-database-data-using-objectquery-api.md)
- [Working with pages in the API](https://docs.kentico.com/13/custom-development/working-with-pages-in-the-api.md)
- [Working with form data using the API](https://docs.kentico.com/13/custom-development/working-with-form-data-using-the-api.md)
- [Working with database queries in the API](https://docs.kentico.com/13/custom-development/working-with-database-queries-in-the-api.md)
- [Working with physical files using the API](https://docs.kentico.com/13/custom-development/working-with-physical-files-using-the-api.md)
- [Customizing event logging](https://docs.kentico.com/13/custom-development/customizing-event-logging.md)
- [Using the sentiment analysis API](https://docs.kentico.com/13/custom-development/using-the-sentiment-analysis-api.md)
- [Cloning objects through the API](https://docs.kentico.com/13/custom-development/cloning-objects-through-the-api.md)
- [Serializing objects to XML using the API](https://docs.kentico.com/13/custom-development/serializing-objects-to-xml-using-the-api.md)
- [Writing automated tests](https://docs.kentico.com/13/custom-development/writing-automated-tests.md)
- [Managing database views and stored procedures](https://docs.kentico.com/13/custom-development/managing-database-views-and-stored-procedures.md)

You can also view the [Xperience API Examples documentation](https://docs.kentico.com/13api.md), which is a code snippet library that demonstrates how to perform basic operations through the API (creating, retrieving, updating and deleting of the system's objects).