I've started using ReDoc to publish my documentation but don't have a good way to know what it will look like before pushing it to my web server. I've used http://editor.swagger.io/ in the past and found it pretty useful. Is there anything like that for ReDoc?
Yes, if you use this project: https://github.com/Rebilly/generator-openapi-repo#features
You can use the swagger editor with it. It doesn't render a preview of ReDoc, but you can have a local dev environment running and watch that browser window reload. To start a local dev environment, see instructions from here https://github.com/rebilly/Redoc#development
cd ReDoc
npm install
npm start
Alternatively, Docker can be used by just running docker-compose up.