Hire voice AI engineers who answer real calls
Our engineers built a phone agent that answers a multi-branch auto shop's line, books appointments, and calls suppliers back. They work in your repo and your standups, and you interview them before anyone starts.
What you are getting
4 things that decide this
- 01Senior engineers only, each with a voice agent already answering real calls in production, not a demo you cannot inspect.
- 02You interview every engineer before they join, so nobody is assigned to your team from a profile you never saw.
- 03They design the handoff to a human before they tune the happy path, because that is the part a demo skips.
- 04If the fit is wrong, say so and we replace the engineer. Every line they write is yours from the first commit.
The job here, beyond the platform demo
Platforms like Vapi, Retell and Bland will sell you the pieces. Almost nobody tells you who wires them into a phone line that has to survive a real caller, a bad connection and an angry customer.
On ZhoopZhoop, a multi-branch auto repair business, we built inbound agents that answer customer calls and book appointments. Outbound agents call suppliers, collect parts pricing, and hand back a comparison. Twilio routes the audio. Deepgram's Voice Agent runs speech-to-text, text-to-speech and turn-taking, and the reasoning layer decides what to say next. Staff see every call, transcript and quote across every branch on one dashboard.
That build is what separates this role from a chat engineer. Turn-taking has to survive interruption, not simply parse text. Latency is a phone call the caller can hang up on, not a spinner they will wait out.
What they take off your roadmap
Turn-taking tuned against real callers
Endpointing that handles pauses, interruptions and background noise, adjusted against actual call recordings instead of a vendor's default settings.
Barge-in handled without confusion
A caller who talks over the agent gets heard, not ignored. The agent stops, listens, and picks up the thread instead of repeating itself.
Escalation to a human, designed first
A clear path for the call the agent should not finish alone: which line it rings, what happens if nobody picks up, and what the caller hears while it waits.
Latency treated as architecture
Speech-to-text, reasoning and text-to-speech are chosen and connected to keep the gap between a caller finishing a sentence and hearing a reply short enough to feel like a conversation.
- Call connectsTwilio routes the audio
- Speech inDeepgram transcribes, tracks turns
- Agent decidesAnswer, ask, or escalate
- Human handoffIf it should not finish alone
- LoggedTranscript and outcome saved
The escalation path is designed before the happy path, not bolted on after launch.
Phone lines we have already put an agent on
How hiring works
- 01
Tell us what the call should do
A free call about the phone line, the volume and what a caller needs to walk away with. If voice is the wrong channel for your problem, you will hear that on the call.
- 02
Meet the engineers
We shortlist people who have tuned turn-taking against real callers, and you interview them. Say no and we go back to the shortlist.
- 03
They embed
Your repo, your standups, your ticket system. One of our engineers owns call quality and is named as the person accountable for it.
- 04
They hand over
The agent logic, call transcripts and escalation rules, plus someone on your team trained to run it. Where a client would rather we kept tuning it, we do that under a service level we agree. The first 2 months of support and maintenance are free, with every build.
Stack
Voice and telephony
- Deepgram Voice Agent
- Twilio Programmable Voice
- Twilio WhatsApp Business API
Reasoning and orchestration
- OpenAI
- Claude
- Function calling
Data and infrastructure
- FastAPI
- PostgreSQL
- Redis
- WebSockets
- AWS
- Docker
Practices
- Call transcript review
- Escalation-path design
- Latency budgeting
- Live call monitoring
Tell us what your callers are running into
Bring the call volume, the worst-case call you cannot afford to lose, and who should pick up when the agent hands off. The scoping call is free, and you will leave it knowing whether voice is the right channel.
01How is this different from buying a voice AI platform directly?+
A platform like Vapi, Retell or Bland gives you the pieces. We give you an engineer who has already wired those pieces into a phone line that survives real callers. They tuned turn-taking against actual call recordings and designed the escalation path before launch. Either route often lands on the same platform. Making it hold up under real callers is the part that differs.
02Can we swap the engineer if the scope changes?+
Say the word and we swap them out. You interviewed them, so this is rare, and it stays our problem rather than becoming a hiring cycle you have to run again.
03Can the engineer review a bad call with us live, or is it all async?+
A daily overlap with your hours, fixed before anyone starts. Call reviews and tuning happen while both sides are awake, because listening to a bad call together is faster than describing it in a ticket. We agree the window during scoping and it does not move without you.
04Who owns the call transcripts and the agent logic?+
All of it is yours from the first commit: the transcripts, the escalation rules and the agent's decision logic. Nothing about how your phone line runs sits behind a vendor you cannot see into.
05What actually drives the cost of a voice AI build?+
Call volume and how many situations the agent has to handle before escalating, more than anything else. A single call type is quick; multiple languages, compliance rules on what can be said, and integration with an existing phone system are the work. Scoping calls are free. Every build starts with a fixed-fee Blueprint: an engineer reads your real systems and writes the plan, with a fixed price for each milestone rather than a guess. The fee is credited in full against the build, and if the plan isn't one you'd act on, you don't pay for it.
Read next
- Voice AI agent development →Us owning the voice agent build outright.
- AI agent development →Agent builds outside the phone channel.
- should an AI receptionist handle emergency calls →Why the escalation path comes first.
- hire AI agent developers →For agent work beyond voice specifically.
- an AI receptionist for a multi-branch auto shop →The build behind this page's proof.
- hire Twilio developers →For sender registration and delivery once the call routes.
