Topicbraid: MQTT Design

Topicbraid is an offline workbench for reasoning about MQTT topic namespaces and access-control rules. The app opens straight into a single dashboard built around a worked broker scenario. At the top, the Authorization probe lets you pick a principal, choose Subscribe or Publish, and type any topic — you get an instant Allow or Deny verdict computed with real MQTT semantics: deny rules take precedence over grants, QoS ceilings are enforced, retained publications require explicit permission, and $-prefixed system topics are never matched by a leading wildcard. Below it, the Observed namespace tree rolls up message counts and byte totals for every branch, the ACL scope chart plots the wildcard breadth of each rule (green for allow, red for deny), and the privilege findings ledger automatically flags risky grants. FEATURES - Live Allow/Deny probe with correct + and # wildcard matching - Deny-precedence evaluation, QoS ceilings, retained-flag checks - Indented topic tree with per-branch message and byte rollups - Wildcard-breadth chart across the full rule set - Automatic findings: unbounded # subtrees, retained QoS 2 write grants PREMIUM BY DESIGN One-time paid download. No account, no ads, no analytics, no tracking, and no network access — everything runs on your device, fully offline.