Multiple devices using single Auth token

Multiple devices were sharing single template, used to work fine but now it is not working.
Is the feature disabled from Blynk side?

[Moderator note - topic title updated to reflect the actual issue. The topic title was originally “Multiple devices using single template” but the issue is actually caused by sharing the same Auth token across multiple devices]

You can have multiple devices based on the same template, if your subscription allows those devices.
I suspect that you might mean something different though, so maybe it would help if you explained more.


I have the same problem,
a single template managed multiple raspberries with node-red installed.
Now it seems that only the last device to which was “Deployed” works correctly excluding the others.
Until a few days ago everything was working fine.
I have a PLUS plan.

It would be nice if one of you guys provided more information.


I have used the same template id in two different devices, earlier both the devices used to work fine, but now only the latest device which connects to the blynk server works.

Edit : Two different sketches are uploaded in two different microcontrollers but they both have the same template id and device name (or auth token, if using legacy sketch format, which I am using in my case). So blynk would treat two different microcontrollers as one device.
Hope now I am clear to you.

Not really.

Are you saying that both pieces of hardware are running sketches that use the same Auth token?

In Blynk IoT, when you create a device based on a template then it generates three lines of firmware configuration, available in the web console > Device > Device Info screen.
These three lines are template ID and template name (which are the same for all devices) and Auth token, which is unique for each device.

You seem to be saying that you’ve created one device from your template and are using the same Auth token in the code running on multiple pieces of hardware.

Is this the case?

The more information you can provide, and the more detailed your explanation, the sooner you will get an answer to your issue.


1 Like

Yes I am using one auth token in two different hardware. It used to work fine up until now.

You should probably read this…

I said then…

“In Blynk IoT, licencing is based around devices and users, with limits set on each by the subscription plans. As far as I’m aware, Blynk don’t currently prevent or specifically look for another device connecting with the same auth token as one is already connected. But, think about how you would approach this if you were Blynk and you were looking to protect your revenue by preventing fraudulent use of multiple devices via auth token sharing. If it was me, I’d implement a system where if there was already an Always On connection with a specific auth token, and another connection was requested with the same auth token, I’d terminate the first connection and accept the second connection.

It may not work that way at the moment, but Blynk would be crazy not to implement this sort of checking in future.”

Looks like my prediction came true!


Seems fair. It was good while it lasted, thanks.

1 Like

@DavideD were you also sharing the same Auth token on on multiple Node-Red connections?


Yes, unfortunately yes.
Now I have to review everything, I understand and partially justify this problem. As already widely discussed, I find it right to protect the rights of those who have ideas and implement them, only we must also consider that this app is used by many hobbyists who have contributed at no cost to making it grow and develop. The more limitations will be created, the more people will be discouraged from using this application. It is a scale on which the right weights must be placed, otherwise the hobbyist will no longer be interested in using it.
I think that the particular condition was known to the developers and such important changes can create inconvenience for those who use this application, sometimes a warning or an announcement to users would be a sign of collaboration even if it is assumed that the projects have been developed according to a of rules.
I only have 4 devices and a single dashboard with 4 switches…For convenience, the devices had the same token so I was able to develop the idea in a very short time. If at this point I can take the opportunity to ask for a suggestion, I would need to maintain a single dashboard with various types of controls that act on different tabs, therefore with different tokens.
Thank you for your cooperation.

And I add one more question. Is it possible to have a card with 2 tokens?

It’s always been the case that you should only have one Auth token per device, and this has been true right from when I started using Blynk more than 6 years ago.
Blynk have clearly decided to implement a system that prevents people from “cheating the system” by sharing Auth tokens across multiple devices.
I don’t think it needs them to pre-announce that the system now enforces what should always have been a rule, but that’s just my opinion.

You’ve not explained much about how you’re using Node-Red. My whole home automation system is based around Node-Red and Blynk, but I don’t run any Blynk code, or have any Blynk Auth tokens on any of my ESP devices. I use the Blynk IoT contrib for Blynk so the only thing that Blynk is a single Node-Red connection that uses a single Auth token.
Node-Red talks to my ESP devices via MQTT, and Blynk is totally unaware of these devices. I have around 25 devices connected to Node-Red, most of which either feed data to MQTT then on to Blynk, or which can be controlled from Blynk. But, as far as Blynk is concerned I have just one device, which is my single Node-Red connection.

The limiting factor is usually the number of datastreams available to communicate with Blynk, and the number of widgets available - all of which are limited by your subscription.

More info on my setup here…


Yeah… Just want to confirm that since the last deployment, we no longer allow multiple connections with the same auth token. The main goal here however was to optimize the server performance, and the above result was a side effect. Which actually fits well in our current business model.

1 Like

Ok Pietro and Dimitri, we will adapt to what is foreseen by your correct and justified business model. What I mean is that it will still have a significant impact on users. I understand your distribution model Peter and certainly given what I’m going through I will treasure it. I’m not a computer engineer much electronic so I think I have set up my cards incorrectly, now I will try to best adapt my distribution to get optimal operation.
I must admit that although I have opted for a Plus plan I will probably have problems adapting all my inputs and as previously mentioned all these limitations will be decisive for hobbyists who will be faced with choices. Having said that, can you answer my two previous questions? i.e.: how can I have a dashboard with commands on several cards, therefore with different tokens and if it is possible that only one card can be authenticated with 2 different tokens.
Thank you

I don’t really understand your questions, and I suspected that if you read the link I provided then you’d understand the options available to you.

When you talks about a dashboard with commands for several cards, I assume that you’re talking about a Blynk dashboard rather than a Node-Red dashboard?
The link to my latest post in my Node-Red MQTT topic certainly does explain how I do this.
The solution is not to run any Blynk code on your devices (cards as you call them), and therefore not to have Auth tokens associated with them. The only place where an Auth token is used is when you create the connection in Node-Red.
Re-read what I said earlier about me having one Auth token that controls 20+ devices because Node-Red acts as a gateway between Blynk and the devices.

I do t think that’s possible, and as I’m sure you’re beginning to realise now, not desired either, because you don’t use tokens on your devices (cards) when using Node-Red with my scenario.


I haven’t read yet because I’m using my phone and I don’t have the possibility to use my pc with my projects until tomorrow. I mean a blynk dashboard, I would like to have a single dashboard with which I can command different tabs.
My question about a card with two tokens is because if I can’t do it I have to radically revise my projects and this takes time.
In this case node-red has nothing to do with it, I’m talking exclusively about blynk dashboards

Do you mean tabs, or devices?

A Blynk dashboard can only display data/widgets relating to one device. You can potentially work around this by sending data from one device to another using automations, the REST API or via Node-Red.
If you’re already using Node-Red then that would be the route I’d suggest.

Your projects will need significant work whichever route you take.

Node-Red is a method of sending data from a variety of devices to a single Blynk dashboard, and to use widgets on that single dashboard to control multiple devices. Once you’ve read the link I provided you will understand better, until then there’s not much point in discussing it further.


Oh Pete the more you answer me the sadder I get…thanks for the replies, I think you clarified the subject enough…but I think at least a couple of cards/devices could have been tolerated instead of having such a restrictive system

The whole principal of Blynk is that each device has a unique identifier (Auth token) which validates that device with the server. When that device connects or disconnects from the server, it is shown as being online or offline in the app/console.
Having multiple devices sharing the same Auth token messes-up this unique device identifier system, as well as allowing people to exceed their device quota.

So, it’s always been one unique Auth token per hardware device, but this hasn’t previously been unforced, but now it is.


1 Like