Assuming you are talking about CommCareHQ as hosted by Dimagi on our SaaS option, as self-hosting would have different answers (IE: That would be 'free" in the sense that there wouldn’t be licensing fees, but it would cost money to pay for servers and the other answers would vary dramatically based on what is being paid).
- Whats the question limit permitted per survey?
There’s no hard limit on this, as it varies by device how many questions can work. It’s also possible to make forms which have very complex logic which become unusable even if the question count isn’t excessive.
Lots of people have hundreds (I think even thousands) of questions in their forms without problems.
You can read about pricing on this page
CommCare mobile is written in Java, HQ is written in Python. The forms and application packages themselves are deployed in XForms and XML documents with XPath logic engine.
- How difficult it is to build survey?
Very basic surveys can be built easily by anyone, but the system allows you to build entire apps, not just surveys. Teams have deployed IMCI, Ebola Contact Tracing protocols, and even Partograph powered labour delivery monitoring tools with their apps. Support for getting started is available through the Dimagi Academy online learning platform.
- How often can you update the survey questions?
As often as your users have access to the internet. Most apps check for automatic updates once a day.
- How many users can have access?
This depends on pricing, but the cloud offering is elastically scalable to an indefinite number of users, and the HQ backend has proven to be scalable past 500,000 mobile users.
The mobile apps can be run Offline First on Android devices. On a browser or on, say, and iPhone, a Web Apps client is available to also run mobile apps.
- Accessible online to fill survey?
Yes, the surveys can be entered online through Web apps. The surveys can also be tested during building through the Live Preview tool.
- *Where data servers is it compatible with? Where does it send the data?
The data sent from forms is XForms data sent with the OpenRosa standards, which our team helped define and deploy, but the only officially supported backend is CommCareHQ with manages the mobile persistence layer stored on devices for beneficiary or other offline longitudinal data. Data destination depends on the hosted environment, with Dimagi’s default cloud being hosted in AWS East region.