De or het indexcode?

The correct Dutch article is:

de indexcode

Rule Words ending in -ode: always de. See the rule

How to use indexcode

the indexcodede indexcode
this indexcodedeze indexcode
that indexcodedie indexcode
our indexcodeonze indexcode
your indexcodejouw indexcode
every indexcodeelke indexcode
which indexcode?welke indexcode?
a big indexcode / the big indexcodeeen grote indexcode, de grote indexcode