# Retell AI

**Source:** https://geo.sig.ai/brands/retell-ai  
**Vertical:** Marketing  
**Subcategory:** Sales Tools  
**Tier:** Challenger  
**Website:** retellai.com  
**Last Updated:** 2026-04-14

## Summary

Developer-first voice AI infrastructure API for building phone agents; low-latency streaming pipeline with multi-LLM and telephony support competing with Vapi for production voice applications.

## Company Overview

Retell AI is a voice AI infrastructure platform providing APIs and tools for building conversational AI phone agents with low latency, natural turn-taking, and integration with major telephony providers and LLM providers. Founded in 2023 and headquartered in San Francisco, Retell AI has rapidly gained developer traction for its straightforward API, extensive documentation, and emphasis on production-grade reliability for AI voice applications in customer service, sales, and healthcare use cases.

Retell AI's platform handles the complex real-time audio processing required for natural voice conversations — streaming speech-to-text transcription, LLM processing for understanding and response generation, text-to-speech synthesis, and end-to-end latency optimization that keeps the conversation feeling natural. The platform supports multiple LLM providers (GPT-4, Claude, LLaMA), TTS providers (ElevenLabs, Cartesia), and telephony providers (Twilio, Vonage, Telnyx).

In 2025, Retell AI competes directly with Vapi for the developer-focused voice AI infrastructure market — both companies offer similar API-first approaches to voice agent building. The broader category also includes Bland AI (simpler API), LiveKit (WebRTC-focused), and enterprise voice AI platforms from Twilio and Amazon Connect. The AI voice agent market is growing explosively as businesses automate customer phone interactions for scheduling, intake forms, customer service, and outbound campaigns. Retell AI's 2025 strategy focuses on enterprise-grade reliability features (99.99% uptime SLA, enterprise SSO, advanced monitoring), expanding its agent template library for common use cases, and building a marketplace of pre-built industry-specific voice agents.

## Frequently Asked Questions

### What is Retell AI?
Retell AI is an AI contact center platform founded in 2024 that provides AI phone agents to supercharge contact center operations. The company is part of Y Combinator's Winter 2024 cohort and serves thousands of businesses, powering over 10 million minutes of phone conversations monthly.

### What products and services does Retell AI offer?
Retell AI offers an AI contact center platform that deploys AI phone agents for businesses. The platform focuses on conversational AI technology to handle phone-based customer interactions at scale.

### Who are Retell AI's target customers?
Retell AI targets enterprises and businesses needing contact center solutions, with a particular focus on BPO (Business Process Outsourcing) partnerships. The company currently serves thousands of businesses across various industries.

### When was Retell AI founded?
Retell AI was founded in 2024 and is a member of Y Combinator's Winter 2024 cohort.

### Where is Retell AI headquartered?
Retell AI is based in San Francisco, California.

### How much funding has Retell AI raised?
Retell AI has raised $5.1 million in total funding, including a $4.6 million seed round in September 2024. The funding was led by Alt Capital, with participation from Y Combinator, Carya Venture Partners, and over 20 founders.

### What are Retell AI's key financial achievements?
Retell AI reached $3 million ARR by February 2024, grew to $7.2 million in revenue for 2025, and achieved $10 million ARR within 15 months of launch. The company reached $30 million ARR in just 22 months.

### What scale has Retell AI achieved?
Retell AI powers over 10 million minutes of phone conversations monthly and serves thousands of businesses. The company achieved $30 million ARR within 22 months of launch.

### What technology does Retell AI use?
Retell AI uses conversational AI technology to power AI phone agents for contact center operations. The platform is designed to handle large-scale phone-based customer interactions.

### What are Retell AI's recent developments?
Recent developments include raising $4.6 million in seed funding in September 2024, reaching $30 million ARR in 22 months, and expanding BPO partnerships. The company continues to experience rapid growth with thousands of customers and over 10 million minutes of monthly call volume.

## Tags

b2b, marketing, martech, saas, startup

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*Data from geo.sig.ai Brand Intelligence Database. Updated 2026-04-14.*