I am currently using this Socket.io library to be able to send data from the Adafruit Feather HUZZAH (based on ESP8266) to my NodeJS server. It works like a charm on my local webserver, never failing me. However, when I try the setup with the proper webapp hosted on Heroku, the command SocketIOClient::connect(host, port) fails and no connection is established with the webserver's SocketIO.

Since there is no mention of limitations with HTTPS connections, I assume that I might be doing something wrong. If the impossibility of having HTTPS connection is the case, however, is there any other way to send this kind of data through web sockets to a NodeJS server hosted on Heroku?

  • probably not an arduino question. But it is also hard to know what your doing when you don't post any code or error messages. "Fails" can mean a lot of different things.
    – Chad G
    May 14, 2018 at 16:42
  • a lot of tls stuff doesn't work on the 8266 because of lack of power and the shared CPU
    – dandavis
    May 15, 2018 at 0:15

1 Answer 1


For anyone having the same issues with SocketIO and the ESP8266, this issue on Github explains how I solved it:

When specifying the host, avoid including the http:// or any other trailing slashes. So it became String host = "something.herokuapp.com";

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