> For the complete documentation index, see [llms.txt](https://docs.ifreeq.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ifreeq.com/developer/configure-in-platform/function-definition/overview.md).

# Overview

Defining product features is the first step in product development. Product functions are completed by a combination of 3 parts, including standard functions, custom functions, and cloud functions.

Standard functions: common functions of a product category 

![](/files/-MBnf-crBNwTfTxwRtkc)

Self-defined functions: If standard functions do not meet your requirements, define custom functions. DPs are abstract representations of product functions, each of which can be defined by different functional types.  

![](/files/-MBnfANoIEfgNXsxnX7L)

Cloud functions: Timer and web page redirection are available. The Tuya Cloud's timer function allows you to set the on/off time and intervals and does not require hardware development. The web page redirection function allows you to go to a web page from the app, for example, go to an online mall or the product user manual page. 

![](/files/-MBnfGJr8QzBEliGZDGZ)

 1、[Standard Functions](https://docs.tuya.com/en/iot/configure-in-platform/function-definition/standard-functions)

2、[Custom Functions](https://docs.tuya.com/en/iot/configure-in-platform/function-definition/custom-functions)

3、[Cloud Functions](https://docs.tuya.com/en/iot/configure-in-platform/function-definition/cloud-functions)