Sierra builds conversational AI agents for enterprise customer-experience workflows, replacing tier-1 support teams.

Enterprise Voice Agents · Series D $950M

Enterprise Voice Agents

Series D

$950M

HQ

ElevenLabs builds real-time text-to-speech and voice-cloning models with support for 29 languages and ultra-low latency.

TTS / Voice Synthesis · Series D $500M

TTS / Voice Synthesis

Series D

$500M

HQ

Parloa builds no-code conversational AI agents for European enterprise contact centers, specializing in voice and omnichannel automation.

Enterprise Voice Agents · Series D $350M

Enterprise Voice Agents

Series D

$350M

HQ

Decagon builds AI customer-support agents that handle ticket resolution, live chat, and voice calls for mid-market and enterprise SaaS companies.

Enterprise Voice Agents · Series D $250M

Enterprise Voice Agents

Series D

$250M

HQ

Sesame builds fast, high-fidelity voice models for conversational AI with a focus on multilingual support and low-latency inference.

TTS / Voice Synthesis · Series B $250M

TTS / Voice Synthesis

Series B

$250M

HQ

LiveKit provides open-source infrastructure for real-time audio and video, powering voice-agent orchestration and WebRTC-based communication.

Voice Agent Infrastructure · Series C $100M

Voice Agent Infrastructure

Series C

$100M

HQ

Cognigy builds enterprise conversational AI for customer service, supporting voice, chat, and omnichannel deployments.

Enterprise Voice Agents · Acquired NICE

Enterprise Voice Agents

Acquired

NICE

HQ

PolyAI builds conversational AI for enterprise contact centers, specializing in restaurant reservations, hospitality, and logistics support.

Enterprise Voice Agents · Series D $86M

Enterprise Voice Agents

Series D

$86M

HQ

Deepgram provides deep-learning-based automatic speech recognition and text-to-speech APIs for real-time transcription and voice synthesis.

STT / ASR · Series C $130M

STT / ASR

Series C

$130M

HQ

Cartesia develops ultra-low-latency voice models including Sonic, achieving ~40ms time-to-first-audio for real-time conversational AI.

TTS / Voice Synthesis · Series B $100M

TTS / Voice Synthesis

Series B

$100M

HQ

Vapi provides a developer platform for building and deploying voice AI agents with sub-second latency and flexible integrations.

Voice Agent Infrastructure · Series B $50M

Voice Agent Infrastructure

Series B

$50M

HQ

Wispr Flow makes an AI voice-dictation app that turns natural speech into clear, formatted text in any application across Mac, Windows, iPhone, and Android.

Voice Dictation · Series A $25M

Voice Dictation

Series A

$25M

HQ

Synthflow offers a no-code platform for building voice AI agents, targeting SMBs and solo entrepreneurs without technical resources.

Voice Agent Infrastructure · Series A $20M

Voice Agent Infrastructure

Series A

$20M

HQ

Resemble AI provides voice cloning and custom text-to-speech APIs for gaming, entertainment, and call-center applications.

TTS / Voice Synthesis · Series B $13M

TTS / Voice Synthesis

Series B

$13M

HQ

DeepL provides neural machine translation and launched DeepL Voice in 2024 for real-time speech-to-speech translation.

Speech Translation · Series C $300M

Speech Translation

Series C

$300M

HQ

Dialpad provides a cloud business communications platform with built-in voice AI for real-time transcription, sentiment analysis, and agent coaching.

Contact Center AI · Series F $170M

Contact Center AI

Series F

$170M

HQ

Cresta provides real-time AI coaching and automation for contact-center agents, analyzing voice and chat to improve sales and support outcomes.

Contact Center AI · Series D $125M

Contact Center AI

Series D

$125M

HQ

Kore.ai provides an enterprise conversational AI platform for contact centers, covering voice, chat, and automation across 100+ channels.

Enterprise Voice Agents · Growth $150M

Enterprise Voice Agents

Growth

$150M

HQ

Observe.AI provides voice analytics and agent-assist tools for contact centers, analyzing 100% of calls for compliance and coaching.

Contact Center AI · Series C $125M

Contact Center AI

Series C

$125M

HQ

SoundHound AI builds a voice-native conversational AI platform powering in-car assistants, restaurant drive-thru and phone ordering, and enterprise agents through its Amelia platform.

Enterprise Voice Agents · Market cap $3.2B

Enterprise Voice Agents

Market cap

$3.2B

HQ

AssemblyAI provides AI-powered speech-to-text APIs with sentiment analysis, speaker diarization, and real-time transcription features.

STT / ASR · Series C $50M

STT / ASR

Series C

$50M

HQ

Voiceflow provides a collaborative platform for designing, prototyping, and deploying conversational AI agents across voice and chat.

Voice Agent Infrastructure · Series B $15M

Voice Agent Infrastructure

Series B

$15M

HQ

Sanas builds real-time accent conversion technology for contact-center agents, translating non-native accents to standard dialects on live calls.

Accent Conversion · Series B $65M

Accent Conversion

Series B

$65M

HQ

Yellow.ai provides a conversational AI platform for customer service and employee support with voice, chat, and automation features.

Enterprise Voice Agents · Series C $78.2M

Enterprise Voice Agents

Series C

$78.2M

HQ

Hume AI builds empathic voice models that detect and generate emotional prosody in speech for more human-like conversational agents.

Emotion & Prosody Models · Series B $50M

Emotion & Prosody Models

Series B

$50M

HQ

Bland AI offers a platform for deploying outbound and inbound phone-based conversational agents at scale.

Voice Agent Infrastructure · Series B $40M

Voice Agent Infrastructure

Series B

$40M

HQ

KUDO offers a cloud-based platform for multilingual meetings and events with AI-assisted interpretation and real-time translation.

Speech Translation · Series A $21M

Speech Translation

Series A

$21M

HQ

Speechmatics offers automatic speech recognition in 50+ languages with real-time transcription and on-premises deployment options.

STT / ASR · Series B $62M

STT / ASR

Series B

$62M

HQ

WellSaid Labs creates synthetic voice avatars for corporate training, e-learning, and media production with studio-quality output.

TTS / Voice Synthesis · Series A $10M

TTS / Voice Synthesis

Series A

$10M

HQ

Rasa builds open-source and enterprise conversational AI for on-premise voice and text assistants, popular in regulated industries.

Enterprise Voice Agents · Series C $30M

Enterprise Voice Agents

Series C

$30M

HQ

Murf AI provides a studio-quality text-to-speech platform with 120+ AI voices for video production, e-learning, and marketing content.

TTS / Voice Synthesis · Series A $10M

TTS / Voice Synthesis

Series A

$10M

HQ

Lindy builds AI personal assistants that handle email, scheduling, and voice calls for individuals and small teams.

AI Personal Assistants · Seed $10.7M

AI Personal Assistants

Seed

$10.7M

HQ

Rime develops fast, expressive text-to-speech models optimized for conversational AI and live-agent experiences.

TTS / Voice Synthesis · Seed $5.5M

TTS / Voice Synthesis

Seed

$5.5M

HQ

Retell AI provides APIs and SDKs for building conversational voice agents with sub-800ms latency and built-in telephony support.

Voice Agent Infrastructure · Seed $4.6M

Voice Agent Infrastructure

Seed

$4.6M

HQ

Goodcall provides AI phone answering services for small businesses, serving 42,000+ barbershops, salons, and local service providers.

Vertical Voice Agents · Seed $4M

Vertical Voice Agents

Seed

$4M

HQ

Phonic provides conversational voice surveys and qualitative research tools powered by AI transcription and sentiment analysis.

Voice Surveys & Insights · Seed $4M

Voice Surveys & Insights

Seed

$4M

HQ

Dasha builds conversational AI for voice and text, offering a low-code SDK for developers building phone-based agents.

Voice Agent Infrastructure · Seed $2M

Voice Agent Infrastructure

Seed

$2M

HQ

Arini builds AI phone agents for dental practices, automating appointment scheduling, insurance verification, and patient follow-up.

Vertical Voice Agents · Pre-Seed $500K

Vertical Voice Agents

Pre-Seed

$500K

HQ

Fish Audio builds multilingual TTS and voice-cloning models with support for Chinese, English, and other Asian languages.

TTS / Voice Synthesis

TTS / Voice Synthesis

—

—

HQ

Soniox develops high-accuracy, low-latency speech recognition optimized for conversational AI and telephony applications.

STT / ASR

STT / ASR

—

—

HQ