The Hologram Dashboard and API provide ways to simulate messages coming from a device with any data and topics. Simulated messages will trigger routes just as any real message from a real device. This effectively eliminates the need to use a physical device and connection to debug and control the effects of it's communication, namely routes.
From the devices list, find the device you'd like to simulate and click on it to view details. Select Messaging -> Simulate from device from the side menu and complete the form.
A simulated message will automatically include the REST_API and DEVICE_ topics.
After successfully submitting the form, check the console to see your message. If you want to see all the routes triggered by this message, make sure "All activity" is selected in the console filters.
You can easily run a previously logged device message by clicking the Simulate button shown in the above screenshot from the outbound message row in the console, which will take you back to the simulate form with the fields pre-filled for you.
Simulating System topics, such as _SIMPLESTRING_ or _SMS_, is currently not allowed.
Under the hood, the dashboard is using Hologram's REST API. The documentation for this endpoint is here.