Yes, if your module does not have an SD card connected, it will default to using the on-board SPIFFS (SPI Flash File System). All you need to do is, build the web app and flash it to the SPIFFS. Instructions for building the web app are here, https://github.com/sudomesh/disaster-radio/tree/master/web#setup (if you have trouble building the web app, you can also copy the web app files from the latest release into the `web/static` folder of the cloned repo). Instructions for flashing the web app to the SPIFFS are here, https://github.com/sudomesh/disaster-radio#building-and-uploading-spiffs-image

Note, you can also use the BLE app without flashing anything to the SPIFFS or using an SD. Just uncomment the `-DUSE_BLE` line in the platform.ini file for your board before building and flashing the firmware and then install the DisasterRadio BLE Chatbox App on an Android device.

Let me know if you run into any issues, you can submit them on our github, https://github.com/sudomesh/disaster-radio/issues

-grant (@paidforby)