Ultravox vs Retell AI
Detailed side-by-side comparison to help you choose the right tool
Ultravox
Voice AI
Breakthrough real-time voice AI infrastructure that processes speech natively without ASR conversion, delivering human-like conversational agents with sub-300ms latency at $0.05/minute - 3x cheaper than GPT-4o Realtime while maintaining enterprise-grade performance and scalability.
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Starting Price
CustomRetell AI
🔴DeveloperVoice AI Tools
Voice AI platform for building conversational phone agents with human-like speech, ultra-low latency, and natural turn-taking for call center automation.
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Starting Price
$0.07/minFeature Comparison
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Ultravox - Pros & Cons
Pros
- ✓Dramatically lower costs at $0.05/minute versus $0.15/minute for GPT-4o Realtime
- ✓Superior latency performance with sub-300ms response times
- ✓Open-weight models provide customization and deployment flexibility
- ✓Enterprise-grade scalability with unlimited concurrency on Pro tier
- ✓Built by proven team with WebRTC and real-time AI expertise
Cons
- ✗Still developing direct speech generation capabilities (currently uses text output plus TTS)
- ✗Smaller company with less brand recognition compared to OpenAI or Google
- ✗Limited enterprise track record compared to established voice AI providers
- ✗Open-source approach may not meet IP protection requirements for some organizations
- ✗Newer platform with evolving feature set and limited long-term user feedback
Retell AI - Pros & Cons
Pros
- ✓Ultra-low latency voice responses (sub-800ms) create natural-feeling conversations that don't frustrate callers with awkward pauses
- ✓Modular pricing with 15+ LLM options and 6 TTS providers lets you precisely optimize cost-quality tradeoffs per agent
- ✓Free SIP trunking eliminates per-minute telephony charges — significant cost savings for high-volume deployments
- ✓Built-in production features like batch calling, branded caller ID, PII removal, and AI quality assurance cover real telephony needs
- ✓Webhook-based function calling enables real-time CRM updates, appointment booking, and database queries during live calls
- ✓Chat agent support with SMS adds multi-channel capability without needing a separate platform
Cons
- ✗No self-hosting option — all voice data flows through Retell's cloud infrastructure, which may not meet strict data sovereignty requirements
- ✗Advertised $0.07/min minimum is misleading — realistic production costs with a capable LLM run $0.13-$0.25/min after all components
- ✗Enterprise features (HIPAA, SSO, RBAC) require custom pricing with no published rates, making budget planning difficult
- ✗Younger platform with fewer production case studies and community resources compared to Twilio or Genesys ecosystems
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