Afterlogic WebMail Lite is open-source webmail script for existing IMAP server. All source code is licensed under AGPL v3.
If you wish to help us improve the codebase, add some features or provide a translation to your native language, make sure you have the most recent code downloaded as described here as the process differs from installing the latest stable version.
In WebMail Lite 8 Developer's Guide you can find a number of tutorials for extending the product functionality and integrating it with other applications, as well as documentation for Web API and PHP API.
Instructions on updating the product translations can be found here: Improving and adding translations
Upon making changes to WebMail Lite 8 code, you can send us a Pull Request. Please bear in mind that the product has a modular structure, so you'll need to send a Pull Request in each repository where you made any changes.
Also, you can create a module for our product, and you might wish to use one of the existing modules as a ground. You can upload it to your own repository of course. And if you believe other users of WebMail Lite 8 could benefit from such a module, please let us know about it!