As per title, there are any plans to make the Cluster API open source?
I’m looking at the github repo but at the moment I can’t find anything that lead to the Cluster API usage (searching for cluster or clustering in the repo just end up with empty results)
Please read the announcement of our Cluster API for its open source origin: New product: Cluster API.
For all our open source work have a look here. E.g. our open source routing engine at github.com/graphhopper/graphhopper powers the Routing, Isochrone and Map Matching API.
Yes I’ve read the announcement for the Cluster API and I’ve seen the origin of the Geo Clustering functionality. The question is, since this feature is available in the online GraphHopper API and I think you guys have done some work to integrate the open source tool, you’d release that in the open source repo as well or not?
you’d release that in the open source repo
There are no plans to open source this.
since this feature is available in the online GraphHopper API
As you can see here not everything of our commercial API is open source. But we try hard to make it mostly everything 
and e.g. for the Routing API and our GraphHopper Maps web application we are very close to 100%. And the remaining differences will disappear and are only a legacy.