OMG -- pardon my candor, but if your looking for an App to solve this problem for you, you got bigger problems....
Finding and vetting CoFounder is like finding a soul mate, maybe harder....
Services like this one might help you find good candidates, but they won't help you vet them or "check fit".
Really, its like dating to marriage -- you start with coffee, hang out cuz you both have "chemistry", get excited about potential, and you will know if its a fit or not. Even then, its just hard.
My best advice is once you find someone that is all of the above, move on to talking MONEY... Equity share, roles, contribution/effort, goals for raising capital, etc. AND most of all, the EXIT STRATEGY. Best to be on the page on how its ends (cuz everything ends at some point) to know how it will all work out. What are the potential exit scenarios (IPO, acquisition, bootstrap until?, failure to raise money, run out of money, sickness or death...?) Sounds morbid, but there is a full range of possibilities, and more end early than go to IPO... I think this is how you "know" fitness fastest.
ALSO homework -- Read the Founder's Dilemma, by Noam Wasserman.
I won't put too much faith in is any automated ways to find a 'good fit' for co-founders.
A much better way to find out is to engage with someone in a project or two - and see if that 'chemistry' exists.
Find something meaningful to work on - ideally something that will stretch and test you both.
Just start working together and see how it goes!
What's the downside?
Have a beer/coffee with the candidate? Why rely on a software tool, instead of your gut, especially when you're intending on working with this person for the foreseeable future. You'll get a far better "read" on the person that way. Ask tough questions, and ask them to grill you as well, since this process works both ways.
Zac, visit this link you will find more scientific solution to the challenge you are trying to resolve from long term perspective.
'Chemistry' is EVERYTHING!
You need to spend more time with people. An app for finding a person as important as your spouse?