Doc is probably not so clear. I'll add a paragraph to avoid misadventure you had.

Having 2 mqtt servers in your network seems a little bit strange... Better have them to write to different topics (like the examples you have given domoticz-master/out and domoticz-slave/out) Not so strange: I have one for production, one for tests, and sometimes one other to do specific things ...

Carefully reviewing your conf file, you're using the same MQTT server for both client and slave. It's possible to set Domoticz up like this BUT you have to differentiate both instances, for example naming one domoticz-master and the other domoticz-slave (giving domoticz-master/out and domoticz-slave ...

So the initial values were transferred not by mqtt but via a different mechanism? How was it possible that those worked but the next ones did not? Mechanism is not the same. When creating device (on slave), we read (master) characteristics and current value from Domoticz's internal tables and send ...

Could you try to install (and setup properly) "MQTT Client Gateway with LAN interface"? On both machines. FYI, it manages 'domoticz/in" and "domoticz/out" topics, which are used by Mqtt Sync plugin. It's generally installed on Domoticz, so I didn't mention it into Mqtt Sync README, but I should do ...

MqttMapper uses topic as key for each created device, which is a constant (while device name can easily be changed). Drawback is that when you create two (or more) devices with the same topic, you get duplicate values. There's a way to fix this: using the "key" item. For example: { "MPWR": { "topic ...

Sorry not seeing it in previous...

It seems that nothing is sent on domoticz/out.

Did you install "MQTT Client Gateway with LAN interface" on both machines?

Having a copy of your configuration file (with personal data replaced by xxx or ***) may help. Before having it, can you check you correctly defined a mapping section, like in the example : { "settings": { "configVersion": "V1.0.0", "masterName": .... }, "mapping": [ {"idx": 2254, "allowSlaveUpdate ...

I changed the topic to : "topic": "/Marstek/#", 2025-07-12 15:45:01.525 MQTT Mapper for DR134: 30 a2 01 00 08 2f 4d 61 72 73 74 65 6b 7b 22 70 61 72 61 6d 0®../Marstek{"param 2025-07-12 15:45:01.525 MQTT Mapper for DR134: 73 22 3a 7b 22 64 69 72 22 3a 22 75 70 22 2c 22 69 64 22 3a s":{"dir":"up" ...

Would it be possible to turn debug to "Verbose"?

Could you also check that MQTT topic really is "Marstek" (take care of upper/lowercases)?

Should you use same ("Marstek") topic more than once, ensure you properly set a "key" item for each device.

FlyingDomotic wrote: ↑Saturday 12 July 2025 1:00 I'll provide a new README.md file with a full English version, followed by a full French version, in the same document BUT continuous for each language.

Done, new README.md contains now English version followed by French one!

I'll provide a new README.md file with a full English version, followed by a full French version, in the same document BUT continuous for each language.

I should apologize... Getting back to my code, I discovered it was already able to extract a numbered item from a list for ... a while. Here's an extract of README.md: In certain cases, payload contains lists (represented by [] delimiters). In this case, you have to specify either list index to use ...

I was more looking for "scan all list items, find those having "name"=xxx, find item "value" and use it as value to load device", as using fixed index is not so idiot proof

I agree with @waltervl, even if syntax is correct, this is definitively not a standard JOSN file, where you normally should have all items at the same level. In your case, what you have to explain to MqttMapper is: please scan all list items, find those having "name"=xxx, find item "value" and use ...

I see it picks up the name of the HW I have set on the name device, something I can change ? https://i.imgur.com/3FXcHCg.png Would be cool if I could define the icon's I like to use as well. Icons that can be changed (meaning not forced by Domoticz like temperature) are generic to any Domoticz ...

What happens if you have more then one of the same key ? lets say like this ? { "status": "On", "running": { "status": "Running" } } First one "status": "On" is "item": "status", second one "status": "Running" is "item": "running/status" "default" is just what you use, nothing to do with the source ...

Is it just me or more who get confused with the mix of English and French? It would better to have 2 different readme files. Second it's hard to follow when we don't have an source output from MQTT. So you can see how the source looks like and how the JSON output looks like. I'm thinking using this ...

waltervl wrote: ↑Thursday 10 July 2025 16:26 @FlyingDomotic your help requested in this topic please viewtopic.php?p=327147#p327147
Error MQTT mapper: Duplicate xxxxxx node/key

Fixed!

Problem is that 2 devices are linked to topic "itho/ithostatus", and as this is Domoticz default key for device, 2 of them are hidden. That's why a "key" item has been created. To fix the issue, you may try something like: { "Itho Boiler temp beneden": { "topic": "itho/ithostatus", "key": itho ...