Copy files from cache. Paths are read from .buildcache file in your project source code.

You should use this, if your project is pulling a lot of dependencies during each build. If you store them into cache and during build you just check if they haven't changed, your build time will reduce dramatically.

$ heroku config:add BUILDPACK_URL=https://github.com/ddollar/heroku-buildpack-multi.git

.buildpacks:

https://github.com/heroku/heroku-buildpack-nodejs
https://github.com/zakjan/heroku-buildpack-cacheload#1.0.1
https://github.com/kr/heroku-buildpack-inline
https://github.com/zakjan/heroku-buildpack-cachesave#1.0.1

.buildcache:

code/server/node_modules
code/client/node_modules
code/client/bower_components

How to clear the cache?

Use heroku-repo plugin.

$ heroku plugins:install https://github.com/heroku/heroku-repo.git
$ heroku repo:purge_cache -a appname