WiFiKeyShare lets you easily share your Wi-Fi password by generating a QR code or by writing it to an NFC tag.
The format of the string encoded in the QR code is commonly used and should be recognized by most barcode scanner applications.
The NFC tag is formatted in the same way as Android does since it introduced its "Write to NFC tag" option in Lollipop. That means people running Android 5.0+ won't have to download any specific app to connect to the network after scanning the tag.
Android does not let apps read the saved Wi-Fi passwords, so the user will need the enter them manually for each network. However, the passwords will automatically be retrieved if WiFiKeyShare is given root access.