The console (the one you can see at https://lora.engineering/) is also open sourced: https://github.com/ExploratoryEngineering/congress-console.
The Congress server is written in Go and the console is written in TypeScript. It implements the majority of the LoRaWAN 1.1 spec but currently have no frequency management (it is on our todo list like so many other things). We’ve managed to push about 180 000 messages/minute through it so it performs reasonably well.
If you want to give it a try all you need is a gateway of your choice running the Semtech packet forwarder – most gateways supports this right out of the box. Point the packet forwarder to port 8000 on your server and you are ready to go.
It is a bit lacking in documentation but we are working on it. Please be patient. The API itself is documented at https://docs.lora.engineering/ but this will (probably) be moved into the project documentation Real Soon Now. Until then – please consult the README file - and of course the source.