I built a free MQTT Explorer + Device Simulator to test IoT backends without physical hardware
One problem kept coming up while building IoT projects: backend development would stall because the hardware wasn't ready yet.
So I built a browser-based MQTT Explorer & Device Simulator that lets you develop and test MQTT workflows without waiting for ESP32s, sensors, or PLCs.
Current features:
- Connect to any MQTT broker (TCP/WebSocket)
- Publish and subscribe to topics in real time
- Explore your MQTT topic tree
- Simulate virtual devices
- Send custom JSON payloads
- Test backend APIs before hardware arrives
- Runs entirely in the browser (no installation)
Some use cases I've been using it for:
- Testing IoT dashboards
- Developing Home Assistant integrations
- Validating backend logic
- QA testing MQTT message flows
- Simulating smart home devices
- Industrial automation prototypes
The simulator can mimic things like:
- Temperature & humidity sensors
- GPS trackers
- Energy meters
- Custom devices with your own payloads
The project is still in its early stages, and I'm actively improving it.
Planned features include:
- Device template library
- Payload generator
- Saved broker profiles
- Webhook testing
- Team workspaces
- More protocol integrations
I'd really appreciate feedback from the community.
What features would make a tool like this genuinely useful in your workflow?
You can try it here:
https://mqtt.tanujlabs.com
Feedback, bug reports, and feature requests are all welcome. I'm building this based on real developer needs.