Enketo Express is a full-fledged web application that is often referred to as just "Enketo". It can be used to collect data for any OpenRosa-compliant server.
To install an Enketo Express production server for data collection, follow these instructions.
See the FAQ for some common troubleshooting tips for Enketo Express.
If your organization is already using Heroku, or has particular scaling requirements that Heroku meets well, follow these instructions to deploy Enketo Express on Heroku.