A quick NodeJS client & server for having a Rasperry Pi Zero measure bandwidth & report it to a remote server
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Node Bandwidth Tester

This project is a tiny NodeJS application that was designed to scratch an itch. My wife's family lives on a farm that frequently has bad internet, and their DSL provider has had a difficult time explaining the poor service. I wanted a tiny device that could sit on their network, measure latency & download speeds, and remotely store that data for graphing & analytic purposes.

What I'm Using

  • A Raspberry Pi Zero - $5
  • An 8GB micro SD Card - $5
  • A micro USB ethernet adapter - $10
  • A micro USB charger cable (let's be honest, everyone has a dozen of these lying around)

So for $20 I have a tiny setup that I can plug straight into their DSL and it'll measure 24/7 the quality of service they're getting. With this I should be able to detect patterns (for example after 3 days of running this at home I was able to spot some throttling happening from my own provider...)

You wouldn't have to use a Raspberry Pi - this will work on any computer that can run Node. I just like it on the Raspberry Pi because it weeds out other variables that might otherwise skew the numbers.


  • Capable of logging metrics locally and remotely
  • Executes a bandwidth test that measures minimum, average and maximum speeds (by default calculated every second)
  • Can be directed to measure latency against any pingable address (such as
  • Can measure download speed from any publicly accessible URL (such as any listed on https://linhost.info/2013/10/download-test-files/)
  • Can have a "random" factor for when to run, to help thoroughly test at different times without clogging the pipes
  • Works with NodeJS v0.10 through v6

Environment Variables

All environment variables can either be maintained by the system, or stored in a .env file in the same directory as the client.js file.


  • PING_REMOTE - This is the server that should be pinged to measure latency. I use
  • TARGET_FILE - This is the URL of the large file to be downloaded. I find a 10 meg file to be great (a couple great options are listed here)
  • MACHINE_NAME - The name of the machine running the bandwidth test (useful if you have multiple devices reporting to a remote server)


  • ODDS_OF_RUNNING - A number, 0 through 1, that represents the percent of time the application should run. For example 0.2 would run the script 20% of the attempts, and 1 would run the application every time (the default behavior)
  • LOCAL_HISTORY - Full path to a writable file where a JSON file will be created that stores the metrics of each run
  • REMOTE_SERVER - URL where the server will send a POST that contains machine, datetime, and a JSON stringified value of the results called data
  • REMOTE_API_KEY - A loose security measure where an addition API-KEY is sent in the HTTP header to limit data logging

Running the application

After you have the environment variables defined,

  1. Run npm install to grab the few required packages
  2. Run node client and the test will be executed.

I have node client setup in crontab to run every 10 minutes, with an ODDS_OF_RUNNING of 0.5, which means I'm actually only calculating my speed 3 times per hour. But this does equate to 720 megs a day and 21 gigs a month if you're downloading a 10 meg file, so plan accordingly.

Sample Bandwidth Chart

Bandwidth Chart

Sample Latency Chart

Latency Chart