Recently, I configured OpenWrt on a lot of devices and it's a great firmware for wireless routers. I read a lot about OpenWISP which is:
OpenWISP is a software platform designed to ease and automate the management of networks, with a special focus on wireless networks, mainly used in public wifi, mesh networks, community networks, and IoT scenarios.
OpenWISP 2, launched in December 2016, is the new generation of the software which is gradually replacing OpenWISP 1 and aims to build an ecosystem of applications and tools that make it easy for developers to build custom networking applications in order to bring innovation in the network infrastructure of communities that most need it. [Source]
I think that it would play like an OpenWrt, however, I don't understand it completely.
OpenWISP is a web application composed with a collection of open source software tools, its aim is to allow the creation of customized network management solution, as well as to provide a default application which allows managing an OpenWRT based network.
Imagine it as a scriptable linux/python/django and web based system through which you can manage a fleet of OpenWRT devices.