- Company 1: https://cactusglobal.com/careers/freelance/
- Company 2: https://proofreading.org/about/careers/
Didn't need a certificate in Proofreading / Editing. You have to test edit a few sample papers to get employed. My backgound: software development (but have a Science degree too from years ago).
The work is remote, flexible (you can decline papers) but *not* highly paid. Also quite hard if you get a poorly written paper. I only did it as a stop-gap.
Also: don't know if GPT has finished this market...