If you need proper ranked voting with correct mathematics behind it:
The Condorcet Internet Voting Service (
CIVS) from the university of Cornell.
This works fine for a vote with multiple options but a single outcome, as well as when multiple outcomes are required. (Eg. Everyone ranks a precreated list of "Ideas you might like" in the order they like them best and it outputs the top 3 most liked.)
It also has a (experimental) mode where it supports not outputting the highest voted list, but a representative list with proportional representation. (Eg. In the previous example 66% answered A,B,C and 33% answered D,E,F the normal algorithm would select A,B, and C but that doesn't represent 33% of the the voters. This algorithm would select A,B,D which is proportionally representative)