Null Driver Service
wdio-null-driver-service is a 3rd party package, for more information please see GitHub | npm
Some complex test suites mix browser and API interactions. This service lets WebdriverIO create a lightweight null session for API-only participants, so you don't waste real browser sessions—especially when running against Selenium Grid.
Installation
The easiest way is to add wdio-null-driver-service as a devDependency in your package.json, via:
npm install wdio-null-driver-service --save-dev
Instructions on how to install WebdriverIO can be found here.