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MQTT Control Packet Type & Fixed Header Decoder

Decodes MQTT fixed header control packet types and flags from the first byte.

Notice: engineering verification utility. Use test or de-identified data and verify results independently before relying on them.

How it works

Standard: MQTT Version 5.0 Protocol Specification

Formula: Packet type = First Byte >> 4, Flags = First Byte & 0x0F

Checks: Valid MQTT control packet type (1 to 15)

Calculated locally in browser memory; nothing leaves your browser.

Deterministic local-first client-side execution. Provided as-is without warranty.