Edit: Soooo there is actually a great article on this, here: https://nextjs.org/docs/pages/building-your-application/configuring/environment-variables#environment-variable-load-order The long and short of my issue is that I was using ‘SITECORE_JSS_EDITING_SECRET’ when I should have been using ‘JSS_EDITING_SECRET’ I must have grabbed the environment variable from the docker-compose file, which will of course not match! Thanks to Rich Seal for having…