Now that IRKit service has been discontinued, this guide assumes you've managed to flash the firmware to no longer require internet connection (English, Japanese). I'd recommend auto-translating the Japanese page and using that.
git clone https://github.com/brymck/irkit-cli
cd irkit-cli
go build .
If you're just setting up Wi-Fi connectivity or have reset your IRKit, you can connect to its network (usually named something like IRKitABCD with a default password of XXXXXXXXXX if you've flashed the firmware and reset) and set the Wi-Fi details with something like
./irkit-cli wifi --ssid yournetwork --password yourpassword --wpa
Note that this assumes 192.168.1.1 points to your IRKit.
Now that you've reconnected to your usual Wi-Fi network, you can now configure the name of your IRKit (run dns-sd -B _irkit._tcp):
./irkit-cli config --name
You can listen for infrared with
./irkit-cli messages
And then you can send the payload with
./irkit-cli messages --content <payload>