Question

Recently, we try to update our nonprofitable organization web site, it is a small but global NGO, the best requirement include:

support multi tenant, since we have different sub organization at different region / country, it is important for each individual to be managed individually (better with its own domain name, but back end support by one platform).
support multiple language, it is critical for local organization to use its own language.
each regional organization can add / remove some module, and manage its own members, we assume some of the core module will be mandatory, but other can be optional.

The core function should include:

member management, regional admin, potential member management
campaign management, fund management
member support, etc.

If you know what may be good existing open source platform which can support some or most of those, please share your thoughts here. The preferred language is Java, but will consider other languages, such as PHP, Python, C#, etc.

Answer 1

I have no experience of installing or maintaining CiviCRM, but it seems specifically designed to handle use-cases like yours. For example, quoting mainly from the features page:

support multi-tenant: "create multiple membership levels for multiple organizations and/or chapters".
support multiple languages: "Internationalization and localization make it possible to use CiviCRM in languages and cultural environments other than American English."
each regional organization can add / remove some module, and manage its own members: "customize membership statuses and rules".
campaign management: "register volunteers for projects using events registration feature".
fund management: "allow campaign fundraising".

It is free and open-source software, licensed under the AGPLv3, and written in PHP.