ThunderPhone

About ThunderPhone

ThunderPhone is an integrated voice AI platform for reliable AI phone agents. Instead of stitching together separate transcription, LLM, and text-to-speech vendors, ThunderPhone combines caller audio understanding, model routing, speech output, telephony, testing, monitoring, and integrations in one stack — so agents hear callers more accurately, follow instructions more reliably, and cost less than call centers or component-based voice AI tools. Agents handle inbound and outbound calls over real telephony (native SIP trunking) or an embeddable web voice widget, and speak 47 languages with mid-call language switching. Built in: cold, warm, and human transfers with context preserved, DTMF capture, voicemail detection, knowledge grounding from your documents, AI-graded test calls before launch, automatic quality monitoring on every production call, live supervision with whisper guidance, and A/B experiments. Pricing is pay-as-you-go from 2¢ per minute — no platform fee, no subscription, no seat fees. HIPAA and GDPR compliant, with BAA and DPA available at no extra charge. #1 score on the Big Bench Audio benchmark. Founded in 2025 by Stanford AI Lab and Y Combinator alumni. Be live on a real phone number in about ten minutes: https://thunderphone.com