Google's best model. Live on your phone lines. At scale.
Native speech-to-speech at €0.08/min. +20% better than STT→LLM→TTS pipelines in production A/B tests with our customers.
30 minutes with a voice AI engineer. Volume, pricing, telephony and migration, mapped before you commit.
Onboarding pass
8 of 10 onboarding slots left for September, each one opened and onboarded by a CallShift engineer.
- 1,000,000+ calls handled
- HQ & Data hosted in 🇪🇺 (Paris)
About 20% better than their old pipeline.
In a head-to-head A/B test, uMinds' Spanish-language 🇪🇸 speech-to-speech agents beat their previous Cartesia + GPT-4.1 mini + Deepgram stack on the metric that pays: performance. They run the whole operation across 3 sub-accounts from one place.
And it held up on the very same campaign
“I thought the biggest voice providers would be impossible to compete with. But CallShift focused on what others were missing. With strong bets on models like Gemini, they’ve delivered the quality and pricing that made us move away from other providers. For me, CallShift is the future of voice infrastructure.”
The customer, in their own words
View on InstagramFigures reflect one customer's production configuration and results, not a contractual commitment.
What elite voice AI operators are saying.
The model is public. The infrastructure isn't.
Anyone can call the Gemini API. Turning it into reliable phone calls at volume is the hard part, and CallShift is the only platform that does it in production.
You build it, you maintain it
- The realtime bridge between your telephony and the model, plus concurrency, multi-account, monitoring and failover.
- Or a 3-step relay (STT → LLM → TTS) that adds latency at every hop.
- Text in the middle strips tone and emotion, and garbles emails and phone numbers.
- Three vendors on every call: one lags and the call stutters, one fails and the call drops.
- Stacked bills that climb to ~$0.30/min across providers.
Months of glue code, three points of failure on every call.
Connect your telephony, go live
- One native audio loop: audio in, audio out, no STT → LLM → TTS chain.
- Real-time pacing, fluid interruptions, and emotional nuance actually heard and expressed.
- Direct the voice from the prompt: tone, accent and style change instantly, no voice swap.
- Emails and phone numbers captured accurately, no transcription layer to garble them.
- ~20% better performance, A/B tested, at €0.08/min on a single bill.
Live in minutes, not months.
Pipeline orchestration (Cartesia + GPT-4.1 mini + Deepgram) still runs on this same plan at a packaged €0.20/min, and keeps an edge on complex tool-calling flows. We operate both, so the ~20% is a real, apples-to-apples result.
State-of-the-art voice AI, at real-world scale.
Gemini 3.1 Flash Live, infrastructure for real volume, two ways to build, and tools made for agencies.
State-of-the-art voice AI
The most natural, lowest-latency speech-to-speech available today.
About GeminiBuilt for production volume
No concurrency ceiling. Built for real call volume.
No-code, 1000+ connectors
Make.com, n8n or custom webhooks. Onboard a new client in minutes, no engineering required.
Multi-account access
Every client in its own sub-account, managed from one place.
Migrate without rebuilding
Coming from Retell or a DIY pipeline? Feature parity where it counts: complex JSON, dynamic tool-calling and custom webhooks, so your flows move over as-is.
Run CallShift from Claude.
Drop our skill into Claude and drive your whole environment in plain language: list and duplicate agents, review a campaign's ROI, add contacts, assign SIP numbers, wire up webhooks. It talks to our API for you.
Integrates with
And 1000+ more, or your custom IT stack or telephony...Frequently asked.
There are other speech-to-speech models. Why Gemini 3.1 Flash Live, and why through CallShift?
Gemini 3.1 Flash Live is the current sweet spot for voice AI: intelligence, low latency, Google's worldwide infrastructure and cost, all in one. But the model is only the brain. Bridging it to live calls at scale, with concurrency, multi-account and reliability, is a different job, and it's the one CallShift handles for you. And you're not locked into the model either: the same plan lets you test any other model whenever you want.
What does it cost, and am I locked in?
€100/month gives you platform access with 100 minutes included each month, plus €0.08/min on Gemini 3.1 Flash Live and a competitive packaged €0.20/min on any other model or configuration. No tokens, no sub-provider bills, no hidden fees. And no commitment: it's a monthly plan you can stop anytime. The exact setup, telephony included (Twilio or SIP), is sized together in your free consultation.
Speech-to-speech or pipeline orchestration: which is right for me?
Native speech-to-speech wins on latency, emotional nuance, accuracy on emails and phone numbers, and cost, and it tests ~20% better overall. Pipeline orchestration stays available on this same plan at €0.20/min for use cases that favour it, like complex tool-calling flows, with an extra 100 minutes included each month on those configurations, so you can test and compare other models anytime.
How do I get started, and do I need engineers?
CallShift is in private access: we open 10 accounts per month, because every single one is onboarded by our engineers: telephony, prompts, migration, edge cases. That is where the ROI of voice AI lives, and we refuse to ship accounts we cannot support properly. It starts with a free 30-minute consultation to map your volume, pricing and integration; once your account is open, you build with the API or the no-code interface and deploy in minutes. No engineers required on your side.
Why only 10 accounts per month?
Because the model is only 10% of the work. The other 90% is implementation: telephony integration, prompt design, flows that replicate, edge cases. Our engineers carry that work with every client, and we would rather open 10 successful launches a month than ship 50 accounts left on their own. When a month's batch is full, you can join the waitlist for the next one, at the same locked-in rate.
What about concurrency limits? Can it handle real volume?
Your plan includes 10 concurrent lines by default, matching the telephony industry standard of 1 call per second, enough to call 10,000 contacts in under 3 hours. Need more? Additional lines are €10/month each at public price, with discounts on enterprise contracts. And it scales: one customer completed 50,000 calls in under 3 hours on 45 concurrent lines at 5 calls per second.
Lock in €0.08/min before September ends.
8 of 10 onboarding slots left for September, each one opened and onboarded by a CallShift engineer.