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
At every level of intelligence, ThunderPhone is the most cost-effective option on the market.
ThunderPhone fuses multiple transcripts with direct audio-to-LLM input — so addresses, spellings, and mumbles don't turn into wrong answers.
Read about our technology“I rent.”
“I rent.”
ThunderPhone Storm pairs a fast model with a thinking model, so your script gets followed precisely while the conversation stays snappy.
See the benchmarks“How much ibuprofen can I take?”
replies instantly, ignoring your rule to never give dosage advice
“How much ibuprofen can I take?”
replies instantly
Interruptions, “mm-hms”, overtalk — ThunderPhone is built to handle the messy parts of real conversation gracefully.
Stops mid-word, answers, picks the thread back up.Backchannels like “mm-hm” don’t stop it — interruptions do.
Whether your calls are customer support, scheduling, pre-sales, or more, ThunderPhone can make them run smoothly.
Place or receive calls, or run bulk outbound campaigns with pacing and retries. TCPA-compliant cold outbound available with ThunderHuman.
Runs over real telephony (HD Voice supported) or embedded in your site or app.
Understands accents and mixed-language calls, switching languages mid-conversation.
ThunderPhone is optimized for the details that make or break real-world calls — and compliant with requirements for healthcare, EU, and more.
See enterprise optionsBAA and DPA available at no extra charge.
Visit our trust centerConnect existing telephony without rebuilding routing.
Handle keypad input for IVRs and confirmations.
Callers can barge in or say “mm-hm” without derailing the agent — and cross-talk and background noise don’t either.
Detect and handle voicemail and screeners on outbound.
Cold, warm, and human handoff with context preserved.
Agents answer from your documents with built-in retrieval — upload docs, test search, deploy.
Watch live calls and whisper guidance to the AI mid-conversation.
From a no-code front end to raw API access and bespoke enterprise deployments, ThunderPhone flexes to fit your needs.
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 platformBuild custom workflows directly against the same core voice runtime that powers the platform.
Read the docsCustom deployments, BYO-LLM via ThunderSocket, data residency options, and per-minute cost targets for high volume.
See enterprise optionsThunderPhone is fast to launch and keeps improving itself once you're live.
Explore the platformDescribe the job in plain language, pick a voice, and choose your intelligence level — Spark, Bolt, or Storm.
Bring your own carrier. A guided wizard detects your trunk and verifies it live — no telecom ticket.
Paste a request and the wizard wires up your CRM, calendar, and APIs — or attach MCP servers and knowledge bases in a click.
Each production call is transcribed and scored — no sampling, no review queue.
Misheard names, dropped steps, and dead ends surface on their own.
Agent updates automatically proposed so you can review and apply in one click.
A/B experiments split live traffic between agent variants and report the winner.
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.
ThunderPhone can help you get your calls right even when no other platform can, and save you money while you're at it.