E4 for Developers > E4 streaming server > Using E4 streaming server

Using E4 streaming server

Running on Windows

Updated May, 2018


  • Windows PC running Windows 7 or Windows 8 with Visual C++ Redistributable Package installed (download from here)
  • The E4 streaming server is currently working only with Bluegiga Bluetooth Smart Dongle.
    Driver/Installation guide can be downloaded here (a Silicon Labs account is required)
  • Empatica E4 Sensor with firmware build installed (present if E4 bought after May 2015)
  • Empatica E4’s must be registered to the API key owner to be accessible via the E4 streaming server


Download the latest release of the E4 streaming server for Windows from here


The first time you start the server you will see the settings panel that allows you to set:

  • Your Empatica API Key (you can find yours here, if you don't have one check this support article
  • The IP address the server bind to and clients have to connect to, e.g.
  • The port the server is listening on
  • Manual BTLE: BTLE connections are established manually

Click the "Save" button after the configurations are made.

Using the server

You will see the default view of the server, click the "Start" button.

If the dongle is not connected or there is a problem with communication, (i.e. missing drivers), the discovery won't start and the message "Dongle not connected" is displayed at the bottom.

If the dongle is not connected, plug it in your PC and press the "Refresh" button placed in the bottom left corner. The server will start to:

  • Discover and connect to the E4 device within Bluetooth range.
  • Listen to commands on the address and port specified in the settings panel.

A text below the button tells you that the app is discovering E4s. Follow these steps to connect an E4:

  1. Make sure to keep the E4s not too close to each other and the dongle. The radios can saturate when the antennas are too close, resulting in communication problems.
  2. Switch on your E4. The led starts to blink green.
  3. After few seconds the E4 is visible in the list, showing the device ID and, once bound, the associated TCP connections.
  4. If manual BTLE is disabled, the E4 is automatically connected. Otherwise a button is shown in the "Actions" row to allow for selective connection over BTLE.
  5. While the connection is being established, the E4 led turns light blue. Finally, the led turns blue upon successful connection.
  6. After around 40 seconds, the led will be switched off in order to save battery.
  7. If you want to connect another E4 after the connection is established, then press the "Discover other E4 devices" button and start again from step 1.
  8. When you want to stop streaming from a device, simply switch off your E4 and it will be disconnected.

Running the Server from Other Code or Scripts

The E4 streaming server can be run without GUI, passing the connection information and API key as startup arguments:


EmpaticaBLEServer.exe 11111111111111111111111111111111 8000

When running the E4 streaming server without GUI, the settings won't be saved and are only active during this execution. Also, BTLE connections have to be handled manually through the commands.


When I click "Save" in settings panel, I see the "Invalid Api key" message

Please try to insert again your API Key (you can find your API key here).
If you have still the issue, please contact our support

When I click "Start", I can't get my E4 connected

Try to follow these steps in order to get your E4 connected:

  • Launch the E4 streaming server
  • Check that the dongle is connected (you should see a "Dongle connected" text) at the bottom of the app's window
  • Click the "Start" button
  • Switch on your E4

If the E4 streaming server can't connect to your E4 before memory mode starts and the led turns red, please contact our support writing us your Api key and the serial number of the device you're using. You can find the serial number on the E4 close to sensor's led.