Maybe the lack of doc is intentional, but to have Flask/React app on Heroku, you need:
– https://github.com/ddollar/heroku-buildpack-multi
– to run grunt build in a sub-folder (project/static/Gruntfile.js), add a package.json at the root folder. Based on the knowledge that heroku will run ‘npm install’
{ "dependencies": { "grunt": "^0.4.5", "grunt-cli": "*" }, "scripts": { "postinstall": "npm install -g grunt-cli bower browserify && cd project/static && npm install && cd ../.. && grunt heroku --gruntfile project/static/Gruntfile.js" } }