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Free public beta until December 4, 2026: every course is open, no card needed. After that, the first chapter of each course stays free and full access is a one-time $39 ($19 for up to 100 founding members chosen for helpful feedback). Your progress is kept. How the beta works

topic filter

The pattern a subscriber asks for; it can contain wildcards to match many topics.

A topic filter is the pattern in a subscription; it matches topics level by level, with + standing for exactly one level and # for all remaining levels.

Examples

  • A dashboard subscribes with the filter gh/+/temp to get every bench's temperature.

  • lab/# used with mosquitto_sub receives everything published under lab/, such as lab/hello.

See also

topic single-level wildcard multi-level wildcard
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