Toolkit

Qt toolkit includes different tools for development, such as:

1. Qt Creator - IDE for development, debugging and deployment of application
2. Qt Designer - part of Qt Creator, tool for graphical design of UI
3. Qt Linguist - tool used for internationalization of application.

Mainly, every Qt project can be easily build and deployed without these tools by using different IDEs or editors, but I would encourage you to try out Qt Creator cause it is nicely tuned for Qt projects.