Kingstone Systems

About Kingstone Systems

Kingstone Systems builds AI phone receptionists, intake and qualification agents, booking agents and messaging agents over SMS and WhatsApp. It is listed as a solutions partner on Vapi's own directory and separately names ElevenLabs as a commercial partner. Unusually for a firm this size, it publishes named client work: the iSmile dental clinic and Suncity Rent-a-Car, both in Croatia, plus a multi-agent real estate brokerage deployment.

It sets written operating boundaries with clients before launch and states that it retains responsibility for how deployed systems run afterwards, which is a clearer position on ownership than most firms here take. No team size, founding year or price is published, no address is given, and the site frames operations across the United States and Croatia while every named client is a small Croatian business.

Our verdict

For a clinic or a small brokerage, Kingstone offers two things the larger firms on this page do not bother with: named comparable clients at the same scale, and a written agreement about what the agent will and will not do before it goes live. The exposure is concentration. One person is named on the entire site, so a buyer is taking on real key-person risk with no published team size, no founding year and no address to fall back on. The build also sits a layer above Vapi, with no SIP, latency or interruption-handling detail published, so how the call behaves under load is untestable from outside. A cost article on its site quotes $5,000 to $15,000 in setup plus around $219 a month for a Vapi receptionist, but that is presented as market guidance rather than its own rate, so its price remains unpublished.

Where Kingstone Systems ranks

• Ranked #13 in AI Voice Agencies