The ndeftool is a command line utility to create or inspect NFC Data Exchange Format (NDEF) records and messages, released under the ISC license.

$ ndeftool text "Hello World" id "r1" uri "http:https://nfcpy.org" save -k "message.ndef" print
Saving 2 records to message.ndef.
NDEF Text Record ID 'r1' Text 'Hello World' Language 'en' Encoding 'UTF-8'
NDEF Uri Record ID '' Resource 'http:https://nfcpy.org'

The ndeftool documentation can be found on Read the Docs and the code on GitHub. It is continously tested for Python 2.7 and 3.5 with the aim for close to complete test coverage.