RPC Commands

ThingsBoard executes LwM2M operations on devices via RPC commands. Send them from the REST API, a dashboard widget, or the RPC Debug Terminal. For a full explanation of the RPC model, see Command & Control.

Command Structure

Every LwM2M RPC command has two fields:

{
  "method": "Read",
  "params": {"id": "/3/0/9"}
}

Field	Description
`method`	LwM2M operation name (see table below)
`params`	Target resource and additional options

Targeting Resources

Use either the resource path or a key defined in the device profile:

Format	Example
Resource path	`{"id": "/3/0/9"}`
Path with object version	`{"id": "/3_1.2/0/9"}`
Key	`{"key": "batteryLevel"}`

In the RPC Debug Terminal omit the JSON wrapper — write Read {"id":"/3/0/9"} directly.

Supported Operations

Method	Interface	Description
`Read`	Device Management	Read a resource, instance, or all object instances
`Discover`	Device Management	List available resources on an object or instance
`WriteUpdate`	Device Management	Partial update — change specified resources, leave others
`WriteReplace`	Device Management	Replace resource value(s) entirely
`WriteAttributes`	Device Management	Set NOTIFICATION-class attributes (pmin, pmax, gt, lt, st)
`ReadComposite`	Device Management	Read multiple resources across different objects at once
`WriteComposite`	Device Management	Write multiple resources across different objects atomically
`Execute`	Device Management	Trigger an action (e.g., reboot, firmware install)
`Delete`	Device Management	Delete an Object Instance
`Observe`	Information Reporting	Start observing a resource for changes
`ObserveCancel`	Information Reporting	Cancel a single observation
`ObserveCancelAll`	Information Reporting	Cancel all observations on the device (ThingsBoard-specific)
`ObserveReadAll`	Information Reporting	List all active observations (ThingsBoard-specific)
`ObserveComposite`	Information Reporting	Observe multiple resources in a single request
`ObserveCompositeCancel`	Information Reporting	Cancel a composite observation
`DiscoverAll`	ThingsBoard-specific	Return the full object/resource hierarchy of the client

Read

Read the current value of a resource, instance, or all object instances.

{"method": "Read", "params": {"id": "/3/0/9"}}

# Terminal request:
Read {"id":"/3/0/9"}

# Response:
{"result":"CONTENT","value":"LwM2mSingleResource [id=9, value=100, type=INTEGER]"}

Read by key:

Read {"key":"batteryLevel"}

Read an entire object instance:

Read {"id":"/3/0"}

Discover

List the resources instantiated on an object or instance, returned as CoRE Link format.

{"method": "Discover", "params": {"id": "/3"}}

# Terminal:
Discover {"id":"/3"}

# Response:
{"result":"CONTENT","value":"</3>,</3/0/0>,</3/0/1>,</3/0/2>,..."}

WriteUpdate

Partially update resource values — unspecified resources are not changed.

{"method": "WriteUpdate", "params": {"id": "/3/0", "value": {"14": "+5", "15": "Europe/Kyiv"}}}

WriteUpdate {"id":"/3/0","value":{"14":"+5","15":"Europe/Kyiv"}}
# Response: {"result":"CHANGED"}

WriteReplace

Replace a resource value entirely.

{"method": "WriteReplace", "params": {"id": "/19/0/0", "value": "0081"}}

WriteReplace {"id": "/19/0/0", "value": "0081"}
# Response: {"result":"CHANGED"}

WriteAttributes

Set NOTIFICATION-class attributes on a resource (pmin, pmax, gt, lt, st). See Data Model for attribute descriptions.

{"method": "WriteAttributes", "params": {"id": "/19/0/0", "attributes": {"pmax": 120, "pmin": 10}}}

WriteAttributes {"id":"/19/0/0","attributes":{"pmax":120,"pmin":10}}
# Response: {"result":"CHANGED"}

ReadComposite

Read any combination of resources, instances, or objects in a single request. Non-atomic — resources without a valid value are omitted from the response.

{"method": "ReadComposite", "params": {"ids": ["/3/0/9", "/1_1.2"]}}

ReadComposite {"ids":["/3/0/9","/1_1.2"]}
# Response: {"result":"CONTENT","value":"{/3/0/9=LwM2mSingleResource [id=9, value=75, type=INTEGER], ...}"}

Read by keys:

ReadComposite {"keys":["batteryLevel","updateResult","pkgversion"]}

WriteComposite

Write multiple resources across different objects atomically. All resources must be writable — the operation fails if any single write would fail.

{"method": "WriteComposite", "params": {"nodes": {"/19_1.1/0": {"0": {"0": "00ad45675600"}}, "/3_1.0/0/15": "Europe/Kyiv"}}}

WriteComposite {"nodes":{"/19_1.1/0":{"0":{"0":"00ad45675600"}},"UtfOffset":"+04","/3_1.0/0/15":"Europe/Kyiv"}}
# Response: {"result":"CHANGED"}

Execute

Trigger an action on the device. Can only target individual executable resources.

{"method": "Execute", "params": {"id": "/3/0/4"}}

Execute {"id":"/3/0/4"}
# Response: {"result":"CHANGED"}

Common execute targets:

Path	Action
`/3/0/4`	Reboot device
`/5/0/2`	Trigger firmware update install
`/1/0/8`	Registration Update Trigger
`/1/0/9`	Bootstrap-Request Trigger

Delete

Delete an Object Instance. The mandatory Device Object (ID 3) cannot be deleted.

{"method": "Delete", "params": {"id": "/19/1"}}

Delete {"id":"/19/1"}
# Response: {"result":"DELETE"}

Observe

Subscribe to changes on a resource, instance, or object. ThingsBoard receives a notification each time the value changes.

{"method": "Observe", "params": {"id": "/3/0/9"}}

Observe {"id":"/3/0/9"}
# Response: {"result":"CONTENT","value":"LwM2mSingleResource [id=9, value=28, type=INTEGER]"}

ObserveCancel

End a specific observation relationship.

{"method": "ObserveCancel", "params": {"id": "/5/0/7"}}

ObserveCancel {"id":"/5/0/7"}
# Response: {"result":"CONTENT","value":"1"}

ObserveComposite

Observe multiple resources across different objects in a single request.

{"method": "ObserveComposite", "params": {"ids": ["/5/0/7", "/5/0/5", "/3/0/9"]}}

ObserveComposite {"ids":["/5/0/7","/5/0/5","/3/0/9"]}
# Response: {"result":"CONTENT","value":"{/5/0/7=..., /5/0/5=..., /3/0/9=...}"}

ObserveCompositeCancel

Cancel a previously established composite observation.

{"method": "ObserveCompositeCancel", "params": {"ids": ["/5/0/7", "/5/0/5", "/3/0/9"]}}

ObserveCompositeCancel {"ids":["/5/0/7","/5/0/5","/3/0/9"]}
# Response: {"result":"CONTENT","value":"1"}

ObserveCancelAll

ThingsBoard-specific. Cancel all observations on the device at once. Use before switching observe strategies.

{"method": "ObserveCancelAll", "params": {}}

ObserveCancelAll
# Response: {"result":"CONTENT","value":"8"}  // 8 observations cancelled

ObserveReadAll

ThingsBoard-specific. Return a list of all currently active observations on the device.

{"method": "ObserveReadAll", "params": {}}

ObserveReadAll
# Response: {"result":"CONTENT","value":"[\"/5/0/7\",\"/3/0/3\",\"/5/0/3\",\"/5/0/5\"]"}

DiscoverAll

ThingsBoard-specific. Return the full object and resource hierarchy of the connected client, built from the registration message. Does not send any request to the device — useful for troubleshooting and verifying object versions.

{"method": "DiscoverAll", "params": {}}

DiscoverAll
# Response: {"result":"CONTENT","value":"[{\"url\":\"/\",\"attributes\":{\"ct\":\"110\",\"rt\":\"\\\"oma.lwm2m\\\"\"}},{\"url\":\"/1\",\"attributes\":{\"ver\":\"1.1\"}},...]"}