The best alternatives to Harness are Copycat, Usetrace, and Testfly. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Harness?
AssemblyAI— Speech-to-Text API with superhuman accuracy
This extension is built to ease creating web tests. It is like Selenium-IDE, but for jest-puppeteer (for now). Also, this extension records actions on your browser, so it doesn't need to open up a new Selenium or Puppeteer window to record your actions on it.
Testfly is a tool to hire thousands of verified testers from 150+ countries at a cost of just $1. Over 65,000 verified testers will use your app/site, test the requested features and submit a detailed feedback report with screenshots or video captures.
Svatah is a scalable, robust, cloud based test automation platform which is imbibed in the behavior driven philosophy. Svatah enables you to rapidly design your test in a language agnostic format and supercharges your execution.