xcon-mq

A single-binary, dependency-free MQTT broker. xcon-mq speaks MQTT 3.1, 3.1.1 and 5.0 with QoS 0/1/2, retained messages, persistent sessions and shared subscriptions — no Kafka, Redis or Postgres. One process, embedded storage, a built-in management console.

Highlights

• MQTT 3.1 / 3.1.1 / 5.0 — session/message/retained expiry, topic aliases, subscription options, reason codes, shared subscriptions.
• QoS 0/1/2 with inflight tracking and a per-session offline queue.
• Transports — TCP, TLS (with optional mTLS), and MQTT over WebSocket.
• Auth & ACL — a provider chain (builtin / x509 / jwt / http) enforced on connect, publish, subscribe and delivery.
• Single node — no cluster to operate. High connection counts are a design target, not a benchmarked guarantee.
• Built-in console — a FluentUI management SPA embedded in the binary.

Durability

With storage enabled and sync set to batch or always, an acknowledged QoS 1/2 publish survives a crash. This does not extend to every piece of session state — see Sessions.

Where to next

• Quick start — run the broker and connect a client.
• Configuration — every config key and default.
• Management console — the embedded admin UI.