External USB RTL SDR receiver device?

General Discussion
1

Is it possible to write programs for an external USB RTL SDR receiver device (https://www.rtl-sdr.com )?
SDR

2

Certainly possible if the sdr uses OTC.

sdr android - Google Search (at least one app one Google Play can control a SDR
https://play.google.com/store/apps/details?id=marto.androsdr2&hl=en_US&gl=US).

but with App Inventor? Depends on whether you have access to the SDR's api and whether you can program AI to use FFT (to tune the radio).