call-automation
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Retell AI Turned $5M Into $50M and a Voice on Every Phone Line
A five-person startup out of San Carlos hit $50 million in annual revenue on $5.1 million raised, powering more than 50 million voice calls a month while the giants it competes with spend hundreds of millions buying their way in.
Callbook AI
Callbook AI is a Y Combinator (S26) startup building AI voice agents that make and take business phone calls in English, Spanish, and Portuguese. Founded by Colombians Diego Avellaneda and Daniel Martinez, it began as a plug-and-play AI phone system for Zoho CRM and has sharpened its focus on automated debt collections and portfolio management across Latin America, handling calls, WhatsApp, SMS, and email from a single platform.
Mia Labs
Mia Labs is an Austin-based AI company building Mia, a voice-first conversational platform for automotive dealerships. Marketed as an 'AI super employee,' Mia answers inbound and outbound calls 24/7 across a dealership's sales, service, reception, and parts departments, syncing with dealer management systems, CRMs, and scheduling tools to capture leads, book appointments, and handle routine customer conversations. As of early 2026 the platform served more than 350 franchise dealerships and had raised a $20M Series A, bringing total funding to roughly $29M.
Arini
Arini is a San Francisco-based AI company that builds a voice and text receptionist for dental practices. Its AI agent answers patient calls 24/7, books and reschedules appointments directly into practice management software, and handles insurance and billing questions - aiming to recover the revenue clinics lose when front desks miss roughly a third of inbound calls. Founded in 2024 by Abdulrahman Jamjoom and Rami Rustom, both former engineers on Meta's Threads team, the company went through Y Combinator's Winter 2024 batch and now handles over 15,000 patient calls a day for dental groups and DSOs across the US and Canada.
Loman AI
Loman AI is an Austin-based voice AI platform that answers restaurant phones 24/7. Its AI agent takes pickup and delivery orders, books reservations, answers menu and hours questions, processes payments, and syncs tickets directly into POS and reservation systems like Toast, Square, Clover and OpenTable. Founded in 2024 by Christian Wiens, the company pitches a simple economic case: a ringing phone that no one answers is lost money, so it turns every call into a captured order. Loman raised a $3.5M seed round in August 2025 and says it handles millions of calls and tens of millions in order volume, with early traction concentrated in the pizza category.
Simple AI
Simple AI is a San Francisco startup building enterprise-ready voice AI agents that handle inbound and outbound B2C phone calls. Its agents answer questions, personalize offers, qualify leads, and close and upsell transactions over the phone - the company says they convert and upsell up to 30% more than trained human reps. Founded in 2024 by former Y Combinator software leads Catheryn Li and Zach Kamran, Simple AI runs on a proprietary voice stack with sub-850ms end-to-end latency and raised $14M in seed funding in February 2026.
Quinn Goldstein
Quinn Goldstein is the founder and CEO of YepChat, a Venice Beach-based voice AI platform built exclusively for restaurants. He and his MIT classmate Daniel Ingram launched the company in 2015 to fix the one piece of restaurant technology everyone ignored: the ringing phone. YepChat turns calls into digital orders, routes them intelligently during peak hours, and scores phone health across 18 metrics for brands like Sweetgreen, Tender Greens, Ruth's Chris, and Alfred Coffee. Before YepChat, Goldstein founded the group-activities service Vixzy and spent years as a startup advisor at GCG.
Slang AI
Slang AI builds an agentic voice AI platform purpose-built for restaurants and hospitality. Its 'Superhost' answers every inbound call 24/7 with warmth and precision - booking and modifying reservations, fielding private-dining and event inquiries, recognizing returning guests, and routing high-value requests to staff. The platform serves 2,000+ restaurant locations, has handled roughly 25 million calls from 10 million unique guests, and reports 95%+ guest satisfaction, helping operators stop missing calls and recover lost revenue.
SuperDial
SuperDial is a San Francisco voice AI company that builds agents to handle the endless administrative phone calls between healthcare providers, billing companies and insurers - navigating phone trees, waiting on hold, and conducting live conversations with payer reps. Its agents automate benefits verification, prior authorizations, claim status follow-up, credentialing and provider data attestation, logging structured results directly into a customer's EHR or RCM platform. Founded by Stanford classmates Sam Schwager and Harrison Caruthers (originally as the billing startup SuperBill), the company launched in late 2023, scaled to seven-figure revenue and tens of thousands of calls per week, and raised a $15M Series A in June 2025 led by SignalFire.
HappyRobot
HappyRobot is the AI-native operating system for the real economy, deploying autonomous AI workers that handle phone calls, emails, and complex operational tasks for logistics and supply chain enterprises. Founded in 2022 by Pablo Palafox, Luis Paarup, and Javier Palafox, the company emerged from Y Combinator S23 and has raised $62 million in total funding - including a $44M Series B led by Base10 Partners. HappyRobot's AI agents now serve 150+ enterprise customers including DHL, Ryder, Werner, and Schneider, automating millions of voice minutes and hundreds of thousands of emails annually, reducing appointment scheduling from a week to under 30 minutes and delivering collections ROI exceeding 100x.