De or het mailmigratie?

The correct Dutch article is:

de mailmigratie

Rule Words ending in -tie and -sie: almost always de. See the rule

This word is not in the word lists we use to double-check answers.

How to use mailmigratie

the mailmigratiede mailmigratie
this mailmigratiedeze mailmigratie
that mailmigratiedie mailmigratie
our mailmigratieonze mailmigratie
your mailmigratiejouw mailmigratie
every mailmigratieelke mailmigratie
which mailmigratie?welke mailmigratie?
a big mailmigratie / the big mailmigratieeen grote mailmigratie, de grote mailmigratie