MQTT SimX - Broker & IoT Tools

MQTT SimX is a portable MQTT client and RTU simulator for engineers, developers, and IoT hobbyists. Connect to any MQTT broker over TCP or TLS and test your topics, payloads, and devices right from your iPhone or iPad. SUBSCRIBE & MONITOR • Subscribe with single- and multi-level wildcards (+ and #) • Choose QoS 0, 1, or 2 • Live message log with automatic JSON pretty-printing • See topic, QoS, and retain flag on every message PUBLISH • Compose multiple topic/payload rows • Per-message QoS and retain • Send one row or publish them all at once RTU SIMULATOR • Simulate a Remote Terminal Unit with digital inputs/outputs and analog inputs • Auto-publish telemetry on a set interval, with optional ±noise • Respond to remote command and config messages, replying with an ACK • Telemetry formats: JSON, Text, KeyValue, XML, Raw PROTOCOLS & SECURITY • MQTT 3.1.1 and MQTT 5.0 • TLS connections • Username / password authentication • Clean-session control and built-in broker presets BUILT-IN GUIDE • Field-level help on QoS, retain, wildcards, and more • An in-app MQTT guide with topic, payload, and RTU command examples PRIVACY MQTT SimX collects no personal data. Your connection settings stay on your device, and the app connects only to the brokers you configure. MQTT SimX is a one-time purchase — no subscriptions, no ads, no tracking.