Documentation

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Use Get Start for installation, migration and operations, Build for the SDK, or skills for agent-readable workflows. The references below explain exact configuration and runtime behavior.

Overview

Runtime modelUnderstand what runs in nginx, what belongs to broker authority, and where blocking sinks execute.Choose a tierMatch live data, durable recovery, integrations or governed operations to your customer workload.Install a nodeObtain the exact image’s complete deployment kit, supply private inputs and verify native configuration and delivery.MQTT coverageCheck MQTT version, QoS, transport, metadata and restart behavior against the current declared profile.Migrate from Mosquitto or EMQXInventory effective behavior, map requirements, test a candidate and plan state handling, cutover and rollback with agent-readable skills.License and service boundariesEvery CitusIO tier, including Free, permits production use. Artifact access, updates and support follow the selected agreement.Read the MQTT export measurementsExact workload, image identities, valid attempts and thermal limits behind the October 2026 operating-point table.

Broker

MQTT ingressConfigure MQTT CONNECT parsing, identity variables, rewrite, and broker-ring attachment.Topic routerBound topic routing, fanout, mountpoints, and shard hints at the nginx configuration edge.Session serviceConfigure bounded MQTT session, expiry, offline queue, and inflight delivery limits.Durable storeBind broker state to PostgreSQL and select the acknowledgement policy.Device authenticationConfigure file, mTLS, and JWT/JWKS identity at the stream boundary.ObservabilityExpose bounded metrics, structured operational facts, and daemon snapshots.

Gateways

MQTT over WebSocketAccept browser and firewall-friendly MQTT clients through nginx HTTP Upgrade.HTTPS device ingressAdmit bounded mTLS-authenticated HTTP telemetry into the broker pipeline.MQTT-SN gatewayConfigure constrained-device MQTT-SN ingress and tenant-scoped Topic ID state.CoAP gatewayConfigure bounded CoAP POST ingress through a registered trusted-gateway boundary.LwM2M gatewayConfigure the selected LwM2M registration and telemetry profile over a trusted CoAP boundary.LoRaWAN webhook gatewayAdmit authenticated network-server webhooks and shape canonical broker topics.Sparkplug B profileRecognize the selected Sparkplug B 3.0 topic and lifecycle envelope on the native MQTT path.OCPP 1.6J profileAdmit a selected charge-point action set over the WebSocket gateway with verified identity.

Platform

Admin APIServe read-only inspection, Prometheus output, and governed Enterprise mutations.Rule engine boundaryRoute bounded broker events through validation, enrichment, republish, and bridge actions.Schema validation boundaryValidate telemetry with the bounded CitusIO JSON-object dialect before bridge delivery.Cluster and HA gateConfigure explicit node identity, writer term, generation, readiness, and fail-closed routing proof.AI capability bridgeUnderstand the reserved policy-controlled AI-to-device boundary and its current availability.

Operations

Public C Bridge SDKImplement a target-compatible sink adapter, negotiate the installed ABI and let the bridge host own delivery policy.Operator consoleInspect backend-owned facts, review authorized intents and follow command evidence through the packaged panel.Console surfacesWhat each operator-console page is for, and which questions it must not answer.Governed commandsTreat HTTP acceptance as admission. Completion requires backend reconciliation and audit evidence.Operator CLIInspect redacted daemon snapshots with ngz-iot, the packaged operator CLI.Fenced active–standbyMove traffic after fencing, writer-term acquisition, valid replay and fresh whole-node readiness.Build your first C bridgeCompile, wire, and prove a crash-isolated C sink adapter on the Free image without rebuilding CitusIO.Kubernetes and HelmDeploy a single CitusIO node or the Enterprise two-node topology without letting Kubernetes grant broker ownership.

Runtime

Modbus TCP acquisitionConfigure bounded daemon-owned industrial polling without a disconnected nginx scaffold.OPC UA client gatewayConfigure secure daemon-owned OPC UA client sessions and subscriptions.nginz-iotd configurationConfigure the shared broker authority, rings, durability, rules, observability, governance, and HA.nginz-iot-bridge configurationConfigure blocking data sinks, bounded execution lanes, durable outbox state, and ring attachment.