Share Wifi credentials via NFC tag without special apps

Question

I am looking for a way to create a NFC-tag that shares the wifi credentials of my network without my guests having to have any special NFC apps on their phone (other than whats

Answer 1

As Alex wrote in a comment, you can now (since Lollipop) write a tag containing Wi-Fi credentials directly from the Android Wi-Fi settings: long-tap a network → Write to NFC tag.

It seems to be an NDEF-formatted tag with the application/vnd.wfa.wsc MIME type and a "WPS NFC" token.

The relevant source code can be found in platform/packages/apps/Settings/src/com/android/settings/wifi/WriteWifiConfigToNfcDialog.java.