Can I source international candidates (outside of the United States)?

Yes, SeekOut is global! 

SeekOut's Public Profile search is all public LinkedIn profiles internationally. That's more than 446 million profiles for candidates across all industries.

SeekOut's GitHub search is global and includes more than 28 million software engineering candidates worldwide.

SeekOut's Expert search and Social Network search are also global.

Just remember to change your search location as appropriate.