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MQTT Topic Matcher
Match one local topic filter against ordered topic names with exact wildcard, empty-level and dollar-topic rules.
One filter, Topic lines
JSON match report
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter Topic filter. Plus must occupy one complete level and hash the final complete level.
- Enter Topics, one per line. Empty slash levels are meaningful; an empty topic line is invalid. One final line terminator is allowed.
- Select Match topics and download mqtt-topic-matches.json. The report retains every topic in input order.
Examples
a/+/c matches a/b/c and a//c, but does not match a/c or a/b/c/d. A first-level wildcard does not match $SYS topics.
Limitations
- At most65,535 UTF-8 bytes per filter/topic,10,000 topics,1 MiB combined input,5 MiB JSON and 30 seconds.
- Stricter text admission rejects NUL, C0/C1 controls, Unicode noncharacters and unpaired surrogates. BOM is literal data; no trimming or normalization.
- Shared subscriptions, wildcard topic names, MQTT5 extensions and live publish/subscribe are unsupported. This is not a broker compatibility certification.
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