Payload formatter
Message inspection
MQTT Payload Formatter
Format, minify, and convert MQTT payloads while checking telemetry, command, and event messages.
Use the payload formatter to inspect MQTT telemetry, commands, retained state, and device events without leaving the browser.
Payload workflow
Make message bodies readable before debugging routing.
Many MQTT issues look like broker problems until the payload is formatted. Pretty JSON, minified JSON, Base64, and hex views help separate transport issues from message-encoding issues.
- Pretty-print telemetry JSON
- Minify payloads before constrained device tests
- Convert opaque payloads to Base64 for transport
- Inspect binary-looking values with hex output
Telemetry design
A payload is part of your API contract.
Stable device payloads should make units, timestamps, identifiers, and schema versions explicit. MQTT moves the message; the payload still needs a durable structure for consumers.
- Include schema or version fields when payloads evolve
- Use ISO timestamps or documented epoch units
- Keep command payloads separate from telemetry payloads
- Avoid secrets in retained messages
Debugging
Compare raw and formatted output when consumers disagree.
If a rule engine, dashboard, or database parser rejects a message, check whether the problem is JSON validity, encoding, unexpected whitespace, or binary data transported as text.
- Validate JSON before blaming the subscriber
- Check Unicode and binary boundaries
- Preserve raw payloads when reporting bugs
- Document payload examples near topic examples