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MQTT Topic Scope

The MQTT Topic Scope widget subscribes read-only to topic filters on an MQTT broker in your local network and shows their live values.

Publishing is deliberately unavailable. The widget can watch your broker; it cannot change anything on it.

What you’ll need

  • The address of an MQTT broker on your LAN
  • One or more topic filters

Enter them in the widget’s ⚙ panel.

Settings

SettingNotes
Broker hoste.g. mqtt.lan
PortDefaults to 1883
Use TLSOff by default; turn on for a TLS listener (commonly 8883)
UsernameOptional
PasswordOptional — stored in Windows Credential Manager
Topic filtersOne filter per line, up to 16

Topic filters

Filters use standard MQTT wildcards:

  • lab/temp — that exact topic
  • lab/+/temp — single level, so lab/attic/temp and lab/garage/temp
  • lab/# — everything under lab/

The 16-filter cap is intentional: the subscription set stays bounded, so the widget can’t accidentally become a firehose against your broker.

Full step-by-step guide lands with the public beta.