Is it possible to request data at specific snap times via the RFA api? For example, I want to request bid prices for US bonds at 16:00 EST.
The snapshot or streaming prices from TREP is always real-time, unless you are subscribing to a delayed service. So, all your application needs, is to request a snapshot at that exact moment (1600 HRS).
You can use programming language specific scheduling features, or use OS schedular like cron, to trigger your app into requesting data.