We would like to confirm that we can use whatever we built during the evaluation/trial version with the purchased license.
You can surely keep developing or coding using evaluation versions of the Aspose APIs and once you purchase the license, you only need to set license at the start of the application and the code will run without any limitation. Furthermore, please note that you can test/evaluate the Aspose APIs without any limitation by using free 30-days temporary license as well. Later, you will only need to replace the temporary license with permanent license you will be purchasing.