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SignalK Node Server

An implementation of a Signal K server. Intended to run on embedded devices (e.g. Raspberry Pi, Beaglebone or UDOO).

The server multiplexes data from , NMEA 2000, Signal K and sensor inputs (eg. I2C connected sensors) and provides the data in Signal K format over HTTP and WebSocket. In addition it can provide NMEA0183 over tcp and udp.

Get up and running

Instructions for installation on Raspberry Pi manually or with Ansible.


  • node and npm installed

Get the repo with either git clone or as a simple zip file from and extract it.

Go to the directory where you put the downloaded code and install dependencies with

npm install
[Firewall giving you trouble?](
Start the server with
This will start the server with a sample configuration file and the server will start playing back set of [NMEA 0183]( data from file. The data is available immediately via the REST interface at localhost:3000 both via [https](https://localhost:3000/signalk/v1/api/) and [http](http://localhost:3000/signalk/v1/api/).
A simple way to connect to the WebSocket interface from the command line is to install wscat and use that:
npm install -g wscat
wscat --connect 'ws://localhost:3000/signalk/v1/stream?stream=delta'

If you want to use NMEA2000 data you must to install Canboat. Canboat allows you to use data from Actisense NGT-1 and convert NMEA2000 data to a format that Signal K Node server can digest.

If you have analyzer available on your PATH you can start the server with a sample NMEA2000 data file with bin/n2k-from-file. An error message saying analyzer: not found tells that you need to install canboat.

For getting live data from your NGT-1 you need to figure out what device path your device is mounted on, edit the configuration file to match you path and start server with bin/n2k-from-actisense.

If you have your own n2k data file you can use that with bin/n2k-from-file --n2kfilename your-file-name. Beware that the playback rate is limited in bytes per second - if your data file is from a rich N2K environment you may want to adjust the rate parameter in the settings file.

Now what? Consumers!

Once you have the data streams in place you probably want to use the data or at least see it in a nice format. See Consumers for details.


Please take a look at the different settings files in the settings directory and read the brief intro.

You can specify the settings file via command line with bin/signalk-server -s <path-to-your-settings-file>.

You can also configure the path to the settings file with environment variable SIGNALK_NODE_SETTINGS.

The http port can be configured separately with environment variable PORT. You can also run on port 80 with systemd. Environment variable NMEA0183PORT sets the NMEA 0183 tcp port.

Real Inputs

To hook the server up to your real inputs you need to create a configuration file that connects to your input source and applies the relevant parsers / converters in the provider pipeline.


NMEA 2000 (via NGT-1 & Canboat)

Signal K delta





settings/volare-udp-settings provides an example of NMEA0183 input over UDP port 7777. If you have trouble getting this to work try setting up DEBUG environment variable with export DEBUG=signalk-server:udp-provider and sending manually input with netcat echo '$IIDBT,034.25,f,010.44,M,005.64,F*27' | nc -4u -w1 localhost 7777. This should result in the server logging the NMEA sentence it receives.


Please see example settings files.

Bonjour support

Bonjour support is not activated by default, because it requires operating system support that is not present by default on all platforms. You can enable it by installing mdns with npm install mdns issued in the server's root folder. See also for more information.

Once Bonjour is enabled the server advertises itself via Bonjour. This means that Bonjour-aware software running in the same network can discover the Signal K server and access it. For example the server shows up in Safari at Bookmarks => Bonjour => Webpages.

You can disable Bonjour/mDNS by adding the entry "mdns": false to the config file. See settings/volare-gpsd-settings.json for example.

The server can also automatically discover other Signal K devices and connect to them. See settings/signalk-ws-settings.json for an example. If the incoming data should be treated as data about self the identity in the settings file and in the incoming data need to match or the incoming data should not include context, as the default is self.


You can use a self generated certificate simply by enabling SSL with "ssl":true in the settings file. If no ssl-key.pem & ssl-cert.pem files are found under settings they will be created.


You can log all the input data in pre-Signal K format by adding the log element to your provider pipeline. It creates hourly files with the data from all the configured providers, interleaved/multiplexed with one message per line. The multiplexed log files can be played back with multiplexedlog provider pipeline element.

Server Plugins

Plugin configuration interface is at /plugins/configure. See Server Plugins for more information.

Further Reading


Copyright [2015] [Fabian Tollenaar, Teppo Kurki and Signal K committers]

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.