Anrok, the sales tax solution built specifically for software-as-a-service (SaaS) businesses, today announced the launch of its new platform, along with $4.3M in seed funding co-led by Index Ventures and Sequoia Capital. The platform, which allows internet businesses to determine, calculate, and manage ever-shifting sales tax obligations, arrives at a time when internet SaaS businesses are facing a major shift in the taxability of software.