I use port forwarding if I want to access my local server NodeMCU from internet. However if I use IOT platforms like Blynk, ThingSpeak... then I dont need to care about port forwarding. We can access our device easily using their auth token and URL provided.

So how do these platforms communicate with the NodeMCU? And how can I implement such connection? I am not asking to know/implement the entire IOT cloud platform, I am just curious understand the way they communicate without port forwarding.

It will be very helpful if you share any tutorial link to implement such server.

1 Answer 1


These systems work by having the device connect out from your home network to the a server run by the service.

This outbound connection is bi-directional so the server can send commands back "down" this link as well as the device sending data "up".

The service then proxies commands sent to it to the device.

  • Is there any name of such technology or do they have any specific protocol?
    – Angom
    Commented Aug 21, 2019 at 16:35
  • 1
    Any protocol that uses a persistent connection (e.g. MQTT) will work and no I'm not aware of a generic name for this technique.
    – hardillb
    Commented Aug 21, 2019 at 17:23
  • The generic name I believe is "NAT traversal techniques". en.m.wikipedia.org/wiki/NAT_traversal Commented May 20, 2020 at 16:31

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