Record-setting accuracy,
for calls you can trust.
Big Bench Audio measures how well voice AI models respond to challenging questions. ThunderPhone holds the record, so you can trust it to make fewer mistakes on your calls.
99.4% on Big Bench Audio
ThunderPhoneStorm · Extra Intelligence99.4
Qwen Audio 3.0Realtime Plus99.2
Qwen3.5 OmniPlus Realtime98.7
Step-Audio R1.1Realtime97.6
2–10× cheaper than the alternatives.
At every level of intelligence, ThunderPhone is the most cost-effective option on the market.
Cost / minPublic pricing · typical outsourced rates
US call centerslive human agent
$0.67+per min
Overseas call centerslive human agent
$0.13+per min
Other voice AIVapi · Retell · Bland
7¢+per min
ThunderPhonefull-stack voice AI
2¢+per min
010¢20¢30¢∕∕$1+
ThunderPhone base prices shown — surcharges apply for long prompts, added intelligence, and premium voices.
Competitor comparisons based on public pricing and typical outsourced call-center rates.
Any call, any channel, any language.
Whether your calls are customer support, scheduling, pre-sales, or more, ThunderPhone can make them run smoothly.
Inbound calls & outbound campaigns
Receive calls or launch native outbound campaigns from the dashboard or API. Upload CSVs with up to 5,000 contacts, set timezone-based calling windows and retries, and follow live progress. Explore campaigns.
For TCPA-compliant cold outreach, ThunderHuman is a separate optional service with human agents guided by AI.
Phone, web, or app
Runs over real telephony (HD Voice supported) or embedded in your site or app.
40+ languages
Understands accents and mixed-language calls, switching languages mid-conversation.
Ready for the real world.
ThunderPhone is optimized for the details that make or break real-world calls — and built for the requirements of healthcare, the EU, and more.
See enterprise optionsCode, no-code, or white-glove.
From a no-code front end to raw API access and bespoke enterprise deployments, ThunderPhone flexes to fit your needs.
Platform·No-code
Run production agents from a front end built for operators.
Launch and manage production voice agents from a front end built for operators — knowledge bases, A/B experiments, outbound campaigns, AI-graded test calls, live supervision, and one-click integrations included.
Explore the platformAPI·Code
The same voice runtime, one POST away.
Build custom workflows directly against the same core voice runtime that powers the platform.
Read the docsEnterprise·White-glove
Custom solutions for enterprise.
Custom deployments, BYO-LLM via ThunderSocket, data residency options, and per-minute cost targets for high volume.
See enterprise optionsHears what callers actually say.
ThunderPhone fuses multiple transcripts with direct audio-to-LLM input — so addresses, spellings, and mumbles don't turn into wrong answers.
Read about our technologyOther voice AI
Caller
“I rent.”
Single transcription model makes mistakes
TRANSCRIPT“Hi Ron”
Agent
✕
“
It sounds like you're talking to someone in the background. I was asking if you're a homeowner?
”
Caller
“I rent.”
What each model made of the same audio
TRANSCRIPT A“I rent”
TRANSCRIPT B“Hi Ron”
AUDIO LLM“I rent”
Agent
“
So you rent. And what's your address?
”
Follows your script — even the tricky parts.
ThunderPhone Storm pairs a fast model with a thinking model, so your script gets followed precisely while the conversation stays snappy.
See the benchmarksOther voice AI
Caller
“How much ibuprofen can I take?”
Agent
replies instantly, ignoring your rule to never give dosage advice
✕
“
Take 800 mg every 8 hours.
”
Caller
“How much ibuprofen can I take?”
Agent
replies instantly
“
Let me check on that for you.
”
checking your rule to never give dosage advice
“
Sorry, I can't give dosage advice.
”
Talks like a person, not a phone tree.
Interruptions, “mm-hms”, overtalk — ThunderPhone is built to handle the messy parts of real conversation gracefully.
Interruption timelinetime →
CallerCaller interruptsCaller
“Just the weekend hours?”
ThunderPhone
“We’re open Monday to—”
ThunderPhone
“Saturday ten to two.”
Stops mid-word, answers, picks the thread back up.Backchannels like “mm-hm” don’t stop it — interruptions do.
Live in 10 minutes, and better every week.
ThunderPhone is fast to launch and keeps improving itself once you're live.
Explore the platformEasy setup
Incredibly easy to set up.
Prompt, voice & intelligence
Describe the job in plain language, pick a voice, and choose your intelligence level — Spark, Bolt, or Storm.
Connect SIP
Bring your own carrier. A guided wizard detects your trunk and verifies it live — no telecom ticket.
Add integrations
Paste a request and the wizard wires up your CRM, calendar, and APIs — or attach MCP servers and knowledge bases in a click.
Closed-loop improvement
And then it monitors itself.
Watches
Every real call
Each production call is transcribed and scored — no sampling, no review queue.
Flags
What's going wrong
Misheard names, dropped steps, and dead ends surface on their own.
Suggests
The concrete fix
Agent updates automatically proposed so you can review and apply in one click.
Proves
What actually works
A/B experiments split live traffic between agent variants and report the winner.
We built the voice platform we needed.
ThunderPhone was founded by a team of Stanford AI Lab and Y Combinator alumni who have been working on voice AI since 2024.
Automating a demanding use case — car-insurance pre-sales — we found existing platforms fell short on audio understanding and instruction following, causing mistakes to happen on calls that led callers to hang up. And the platforms' prices were much higher than we thought was reasonable.
So we built our own stack from the ground up to nail the car insurance use case. Then, we turned that stack into ThunderPhone to bring higher performance and lower price to the whole industry.
We've handled thousands of production calls to date, and we'd be glad to show you what our system can do for your use case.
Put your hardest calls
on the integrated stack.
ThunderPhone can help you get your calls right even when no other platform can, and save you money while you're at it.