Vapi

Vapi is the builder's option in this job. It provides the real-time hosting that turns a language model, a transcription service, a voice and a phone line into a working voice agent, and lets you swap every one of those layers independently as better or cheaper options appear. A receptionist built on Vapi can answer around the clock, hold a natural back-and-forth, call functions mid-conversation to check a calendar, create a booking, look up a customer or update a record, and hand off to a person or another system when the call goes beyond its brief. Nothing about that receptionist is pre-built, however. The greeting, the qualifying questions, the booking rules, the failure behaviour and the integrations are all yours to design, test and maintain, normally through its dashboard for configuration and its API for anything serious. The pricing reflects the philosophy: a clear, low hosting fee per minute, with every other component passed through at the provider's own price, so your real cost depends on the stack you assemble. Its own calculator, using common default providers, lands noticeably above the hosting fee alone, and support and capacity packages sit on top for teams that need them. For a solo founder who can build, or who wants an agency to build an asset they control rather than rent a closed receptionist, Vapi is compelling. For a founder who wants the phone answered tomorrow with no project attached, every managed service above it in this ranking is the better buy.

Per-minute hosting fee plus pass-through provider costs. Vapi charges $0.05/min for hosting; transcription, language model, voice and telephony are billed at provider rates, with optional support packages on top.