Voice AI that nails
the calls others fumble.
Other call-center AI platforms mishear callers and stray from scripts. ThunderPhone's integrated stack is more reliable — and costs less.
from2¢/minCheapest full-stack voice AI
accuracy99.4%★ Highest score on Big Bench Audio
Caller audio
fast ASR
fifty Larkspur, Esposito
audio-aware LLM
fifteen Larkspur, Esposito
transcribe ×2
fifteen Larkspur, Esposito
15 Larkspur · Esposito
3 paths agreed
Pricing
2–10× cheaper than the alternatives.
ThunderPhone pricing is all-inclusive, with no platform fee. At every level of intelligence, ThunderPhone is the most cost-effective option on the market.
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.
Audio understanding
Hears what callers actually say.
Other platforms rely on a single transcription model with no backup. ThunderPhone fuses multiple transcripts with direct audio-to-LLM input — so names, addresses, spellings, and mumbles don't turn into wrong answers.
Other voice AI
Caller said“I rent.”
ASR “Hi Ron”
no second transcript
no direct audio input (information lost!)
AI thinks caller said:
Misheard“Hi Ron”
ThunderPhone
Caller said“I rent.”
ASR A “I rent”
ASR B “Hi Ron”
audio input LLM “I rent”
AI thinks caller said:
Heard right“I rent”
Instruction following
Follows your script — even the tricky parts.
Other platforms rely on single fast, non-thinking LLMs, which frequently make mistakes, especially with complex prompts and ambiguous situations. ThunderPhone Storm fuses thinking and non-thinking models to follow instructions more reliably while still responding quickly to callers.
Other voice AI
Your ruleNever give medical or dosage advice.
Caller said“How much ibuprofen can I take?”
Fast model “Take 800 mg every 8 hours.”
No thinking model — your rule is never checked.
Outcome:
Off-scriptBroke your rule
ThunderPhone Storm
Your ruleNever give medical or dosage advice.
Caller said“How much ibuprofen can I take?”
Fast model “Let me check on that for you.”
Thinking model “Sorry, I can't give dosage advice.”
Outcome:
On scriptFollowed your rule
What it does
Any call, any channel, any language.
Whether your calls are customer support, scheduling, pre-sales, or more, ThunderPhone can make them run smoothly.
Inbound & outbound
Place or receive calls. TCPA-compliant cold outbound available with ThunderHuman.
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.
Built for production
Ready for the real world.
ThunderPhone is optimized for the details that make or break real-world calls — and compliant with requirements for healthcare, EU, and more.
Native SIP trunking
Connect existing telephony without rebuilding routing.
DTMF capture
Handle keypad input for IVRs and confirmations.
Noise & interruption handling
Stay usable through cross-talk and background audio.
Voicemail & screener detection
Detect and handle voicemail and screeners on outbound.
Transfers
Cold, warm, and human handoff with context preserved.
HIPAA & GDPR compliant
BAA and DPA available at no extra charge.
Level of control
Code, 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
Launch and manage production voice agents from a front end built for operators — testing, monitoring, and integrations included.
Explore the platformapi.thunderphone.comPOST /v1/calls
{
agent_id: "agt_live",
to: "+14155550131",
model: "storm",
metadata: { source: "web" }
}
API
Build custom workflows directly against the same core voice runtime that powers the platform.
Read the docsEnterprise workspace
Custom deployment · Acme Health
Deployment plan
HIPAA BAA signed
BYO-LLM route · ThunderSocket
Outbound cost target · 3¢/min
Voice
Legal
Route
Enterprise
Custom deployments, BYO-LLM via ThunderSocket, data residency options, and per-minute cost targets for high volume.
See enterprise optionsLive in 10 minutes, and better every week.
Explore the platformThunderPhone is fast to launch and keeps improving itself once you're live.
Easy setup One-time
Incredibly easy to set up.
01
Prompt, voice & intelligence
Describe the job in plain language, pick a voice, and choose your intelligence level — Spark, Bolt, or Storm.
02
Connect SIP
Bring your own carrier. A guided wizard detects your trunk and verifies it live — no telecom ticket.
03
Add integrations
Paste a request and the wizard wires up your CRM, calendar, and APIs automatically.
Closed-loop improvement Always on
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.
Our story
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.
“
Our job is to make ThunderPhone handle your calls at the highest performance today's AI allows, at the lowest prices possible. If we ever fall short, email me personally.
AK
Alex KolchinskiCEO · alex@thunderphone.com
ThunderPhone v2 is now livePut your hardest calls
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.