Can I send a message from one Notecard to another Notecard?

Continuing the discussion from Notecard Note-WBEX-500 + Notecarrier AA: cannot connect to cellular network (green led flashes once):

we envision a direct communication between a notecard and another, in a peer-to-peer fashion…so essentially we would not probably need the notehub. Is this something we can do with the notecards, or they are just meant for collecting data on the field and sending them on the notehub?

No direct Peer to Peer connections between Notecards

For security reasons, one Notecard does not have direct access to another Notecard. All messages must pass through the Notehub in some fashion.

Use an external cloud function to broker messages between devices

The best option is to use something like a AWS lambda function or Google Cloud function to broker passing messages between devices. Messages are routed from Notehub to the cloud function.

This has a couple of benefits.

  1. You can control how one device addresses another device. That is, you can select the identifiers used to establish who is sending messages to whom. The function can map that identifier to the Notecard device UID.

  2. You can control who can send messages to whom.

  3. If you want to do E2E it enables some asynchronous key management as well.

  4. Devices can exchange messages asynchronously, and do not need to be online at the same time.