MQTT Loupe is an intuitive utility to inspect MQTT messages exchanged on an MQTT broker. Connect to any public or local MQTT broker, subscribe to topics and view details of messages being transmitted.

Don't remember that one message or topic? Fire up the search to find it instantly using full-text search through all topics, and results updating live with new hits appearing as they arrive.

With built-in JSON highlighting, this app is perfect for monitoring Zigbee2Mqtt. And if you need to work with binary message payloads, the built-in hex viewer has you covered. Got frequently used topics that are further down the hierarchy? Make them favorites for easy and instant access.

Concerned about security? Let the server's certificate be validated before connecting; you don't have to allow insecure connections based on untrusted certificates. Need more? Provide a client certificate to authenticate yourself against the server.

All features in a nutshell:

- clean and simple interface
- hierarchical topic view
- sidebar with history of recently opened topics
- powerful full-text search capabilities across all topics and for a single message
- search results are automatically updated when new messages arrive
- extended message details, with proper formatting and syntax highlighting of JSON messages
- support for binary message payloads, displayed as either ISO Latin-1 or in a hex view
- easily copy any topic or message value
- authentication with username/password or client certificates
- connect over MQTT or WebSocket protocol
- support for MQTT 3.1.1 and MQTT 5
- support for SSL/TLS
- support for the Server Name Indication (SNI) TLS extension
- support for self-signed certificates
- full server certificate validation
- manage and connect multiple brokers at once
- full support for quality of service