Wholesale VoIP providers for MSPs, ranked on what actually determines whether voice becomes a recurring revenue line or a margin leak: how much survives after billing and taxes, whether the vendor competes with you for the same end customers, and whether the AI roadmap is something you can put on a price sheet today. Viirtue leads because channel-only sales, quote-to-cash automation, and AI voice agents you can actually resell are the combination nothing else on this list matches.