Hello Mike,
First of all thanks for your interest in my work at App Builder. I will try to answer your questions below.
David,
Before I buy your software, which looks very good, I need to ask some questions.
First, I need to develop a few immediate apps. One requires that I show a catalog of images (custom emoji) and allow the user to select one and drag and drop it into texts, emails and other phone tasks with text input. It is very important that this be for Android and IOS and it must allow for in-app purchasing.
App Builder produces HTML5 applications ready to be deployed in mobile and desktop modern browsers. App Builder also produces WebApps, Progressive WebApps and WebExtensions. For other platforms we use Apache Cordova, who provide us the way to build HTML5 applications into various platforms like Android and iOS.
Drag and Drop is not currently supported out of the box by App Builder. We can show images in various ways and react when they are tapped/clicked. You can take a look at the "Report*" applications samples included by the program. Take a look at the Menu -> File -> Samples.
Of course, since App Builder can be extended by thirdparty Javascript libraries and HTML5 code, then maybe we can implement some kind of drag and drop support, or simply look for a way in which we can implement a similar behaviour without the drag and drop.
Second app would require excel-like data grids and mysql for database. Does your app support both?
App Builder is abstracted from any kind of databases. In fact client side applications does not have a very good support for databases, due to browsers vendors limitations. However, as you can see in the Database application sample, we can deal with MySQL databases without problems, just by using certain server side scripts, in the case of the mentioned sample using the PHP language. Such scripts are included in the sample so you can take a look at them.
Datagrid like is supported by the Report control. Again, I refer you to the various "Report*" applications samples includes by App Builder.
How hard is it to create an app, code it and then export to IOS and Android and then get the apps into their respective app stores? I understand that I have to pay for app store licenses for IOS and Android. What else will I need to accomplish this?
Every platform impose their singular and specific requeriments/licenses/fees. You must study the platforms requeriments. App Builder ends with the HTML5 generation, then Apache Cordova enter in the scene to finally get an APK file (for the Android platform). The we need to sign this APK and finally we need to upload it to the appropiate platform store.
Take a look at the below threads for a little more information:
To sign APK files in order to upload it into the Google Play Store:
https://www.decsoftutils.com/support/viewtopic.php?id=178
To get our applications ready into the Apple Store/iOS devices:
https://www.decsoftutils.com/support/viewtopic.php?id=105
What is the main scripting language for your software? Is it HTML5 with Javascript? Php? MySQL?
The scripting language is inspired in VisualNeo and other programs who base their scripts in "actions". The point is to prepare actions easy to use (can be edited in a visual way, for example) for non programmers. Between the "StartJS" and "EndJS" actions we can place any Javascript code we wanted.
We can use the HTML control to include any HTML we wanted too. PHP is supported in the sense that our applications can send HTTP requests how PHP scripts can reply. Aboyt MySQL I talk a little about above: App Builder is abstracted from any database. We can communicate with PHP scripts who uses MySQL, Firebird, SQLite or whatever datase.
Is it possible to use custom jquery controls from 3rd party developers?
It's possible, however, we must to test it. The best is to use the controls included by App Builder, since they are already based in certain frameworks (AngularJS and Bootstrap CSS) and not in others like jQuery mobile. But you can see, for example, how we can use jQuery to parse RSS feeds. Take a look at the RSS application sample.
Is this software being actively supported? How long does it take to get answers on the forum from support? In many cases, I have very tight deadlines and I may need quick support for questions - usually "How do I do this in your program" kind of questions.
I try to answer as quickly as possible Mike. Hope this can help you in some way and thanks again for your interest in my work at App Builder.
DecSoft HTML Compiler include a convenient Command Line Compiler, so you can compile your apps from the console. 
DecSoft NeoPlugins are available in both runtime and designtime flavours to keep your apps as small as possible. 
Design for small screen devices but deploy also (without changes) in larger devices like tablets. 
Take a look at some frequently asked questions about us and our products! 
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