Core State Uplink Data

Reports the current device operating state, uptime, and whether the backend connection is healthy. All values are sent automatically on change and periodically (based on update_period_mins).

Key path: devdata.core

To request current values:

{ "devdata": { "core": null } }

state

Current device state as a single character code.

Configuration variables

• Type: string (single character)
• Sent on: Every state change

Code	State
I	Initialising
B	Boot / starting
U	Unallocated
A	Allocated
E	Error
W	Wiping / formatting
D	DFU mode
P	Provisioning

{ "devdata": { "core": { "state": "A" } } }

ts

System timestamp in milliseconds (device uptime). Useful for correlating events.

Configuration variables

• Type: integer (milliseconds)
• Sent on: With every devdata message

{ "devdata": { "core": { "ts": 987654321 } } }

comm_ok

true when the device has received any MQTT message within devcfg.core.app_timeout_secs. Goes false when the timeout expires with no traffic.

Configuration variables

• Type: boolean
• Sent on: Every state change, periodic updates

{ "devdata": { "core": { "comm_ok": false } } }

app_ok

true when the device has received an application‑level message (anything in the app or devcfg sections) within the timeout. false when only system‑level traffic (pings, etc.) has been seen.

Configuration variables

• Type: boolean
• Sent on: Every state change, periodic updates

{ "devdata": { "core": { "app_ok": false } } }

Related

• Core Config (Downlink) — app_timeout_secs
• State Codes Reference — full list of state codes
• MQTT Overview — how messages are sent