# Connector Builder how-to guide

> This how-to guide explains how to build custom connectors and activities. It provides step-by-step instructions to build connectors
for the following applications:

This how-to guide explains how to build custom connectors and activities. It provides step-by-step instructions to build connectors
for the following applications:

* DALL-E Image Generation – with Personal Access Token authentication.
* SAP S4 ODataV2 – with API Key authentication.
* USPS API Address Validation – with OAuth2.0 Client Credentials authentication.