Over 500 billion minutes of wholesale voice traffic crossed international networks last year, building a market worth an estimated $44.53 billion in 2026 and projected to reach $73.63 billion by 2031. A wholesale voice carrier business purchases termination capacity in bulk from upstream carriers and resells it to downstream buyers — other carriers, MVNOs, call centers, and UCaaS platforms — earning margin through Least Cost Routing on the spread between buy and sell rates, across three revenue streams: voice termination, voice origination, and transit/aggregation. The industry organizes into three tiers: Tier 1 carriers own global physical infrastructure and peer directly with other Tier 1 networks (requiring hundreds of millions in capital); Tier 2 carriers own regional infrastructure and lease capacity elsewhere; and Tier 3 aggregators lease all capacity and compete on service quality and pricing, the typical entry point for new operators. Core infrastructure requirements include a Class 4 softswitch for carrier-to-carrier routing, a Session Border Controller for SIP signaling and fraud protection, near-real-time CDR-based billing, and automated fraud management against IRSF and Wangiri attacks. Route pricing follows the same Premium/Standard/LCR tier structure found across the wholesale voice industry. Compliance is a serious operational cost: US carriers must implement FCC-mandated STIR/SHAKEN call authentication with attestation levels A, B, or C, maintain interconnect agreements defining traffic types and liability, and support Local Number Portability across jurisdictions, while SIP signaling follows IETF RFC 3261. Building a customer base means selling to retail VoIP providers, UCaaS platforms, call centers, MVNOs, and other regional carriers — with white-label reseller capability as a common differentiator. Softtop's turnkey platform supports operators across 150+ countries at every tier, with 50-70% margins achievable through white-label models and smart LCR routing.