Key takeaways
- Transparent modular pricing starting at $0.07/minute with no platform fees and component-level visibility
- No-code agent builder plus full API for both non-technical and developer users
- Enterprise-focused with 99.99% uptime SLA, batch calling, and CRM integrations
FAQ
What is Retell AI?
Retell AI is a voice agent platform for automating phone calls, offering both no-code tools and APIs to build AI agents that can handle customer service, sales, and support calls.
How much does Retell AI cost?
Base infrastructure is $0.055/minute plus voice ($0.015/min), LLM (varies), and telephony ($0.015/min). Total starts at $0.07/minute with typical costs of $0.10-0.20/minute.
Does Retell AI support OpenAI Realtime?
Yes, Retell AI supports OpenAI GPT-4o Realtime at $0.50/minute as an alternative to traditional STT+LLM+TTS pipelines.
Executive Summary
Retell AI is a voice agent platform focused on phone call automation with transparent, modular pricing. The platform offers both a no-code builder for non-technical users and full API access for developers. Backed by Y Combinator, Retell has raised $5.1M and focuses on enterprise call center automation with 99.99% uptime guarantees.
| Attribute | Value |
|---|---|
| Company | Retell AI |
| Founded | 2023 |
| Funding | $5.1M (YC W24) |
| Investors | Y Combinator |
| Focus | Phone call automation |
| Pricing | $0.07+/minute |
Product Overview
Retell AI positions itself as the transparent alternative in voice AI, with modular component pricing that lets customers see exactly what they're paying for. The platform is designed for call center automation—handling customer service, sales, and support calls at scale.
Unlike developer-only platforms, Retell offers a no-code agent builder that non-technical users can use to create and deploy voice agents without writing code.
Key Capabilities
| Capability | Description |
|---|---|
| No-Code Builder | Visual agent creation without coding |
| API Access | Full programmatic control |
| Phone Integration | Inbound/outbound, Twilio, SIP |
| Batch Calling | Automated outbound campaigns |
| Knowledge Base | Document-grounded responses |
| Analytics | Call transcripts, metrics, insights |
Voice and LLM Options
| Category | Options |
|---|---|
| Voices | Cartesia, Minimax, ElevenLabs (each $0.015/min) |
| LLMs | GPT-5, GPT-4.1, Claude 4.5, Gemini 2.0 |
| Realtime | OpenAI GPT-4o Realtime ($0.50/min) |
Technical Architecture
Retell AI uses a traditional STT+LLM+TTS pipeline by default, with optional support for OpenAI Realtime as an alternative. The platform handles telephony integration and provides pre-built functions for common call center tasks.
┌─────────────────────────────────────────────────┐
│ Phone Network │
│ Twilio | SIP | Custom Telephony │
├─────────────────────────────────────────────────┤
│ Retell Platform │
│ ┌───────────────────────────────────────────┐ │
│ │ Voice Pipeline │ │
│ │ ┌─────┐ ┌─────┐ ┌─────┐ │ │
│ │ │ STT │ → │ LLM │ → │ TTS │ │ │
│ │ └─────┘ └─────┘ └─────┘ │ │
│ │ OR │ │
│ │ ┌──────────────────────────┐ │ │
│ │ │ OpenAI Realtime S2S │ │ │
│ │ └──────────────────────────┘ │ │
│ └───────────────────────────────────────────┘ │
│ ┌───────────────────────────────────────────┐ │
│ │ Knowledge Base | Functions | Analytics │ │
│ └───────────────────────────────────────────┘ │
└─────────────────────────────────────────────────┘
Enterprise Features
| Feature | Description |
|---|---|
| 99.99% Uptime | Enterprise SLA guarantees |
| Fallback | Automatic failover |
| CRM Integration | Native and webhook support |
| PII Removal | Privacy compliance |
| Batch Calling | Scheduled outbound campaigns |
Strengths
- Transparent pricing — Modular component pricing with no hidden fees
- No-code option — Visual builder for non-technical users
- Low base cost — $0.07/minute starting price competitive with alternatives
- Enterprise SLA — 99.99% uptime guarantee
- Simulation testing — Built-in testing tools for agent validation
- Batch calling — Automated outbound campaigns at scale
- Phone-focused — Purpose-built for call center use cases
Cautions
- Smaller funding — $5.1M vs Vapi's $25M may limit growth
- Phone-only focus — Less suited for web/mobile voice agents
- Add-ons increase cost — Knowledge base, denoising, PII removal add fees
- Limited voices — Fewer voice options than ElevenLabs
- Traditional pipeline — STT+LLM+TTS latency unless using Realtime
- Newer company — Less track record than established players
Pricing & Licensing
Retell AI uses transparent modular pricing:
| Component | Cost |
|---|---|
| Platform (Infra) | $0.055/minute |
| Voices | $0.015/minute (Cartesia, Minimax, ElevenLabs) |
| LLM (GPT-4.1) | $0.045/minute |
| LLM (GPT-4.1 mini) | $0.016/minute |
| LLM (Claude 4.5 Sonnet) | $0.08/minute |
| Telephony (Twilio) | $0.015/minute |
| OpenAI Realtime | $0.50/minute (replaces pipeline) |
Add-ons:
- Knowledge Base: +$0.005/minute
- Batch Call: +$0.005/dial
- Advanced Denoising: +$0.005/minute
- PII Removal: +$0.01/minute
Typical total: $0.10-0.20/minute for standard configuration.
Competitive Positioning
Direct Competitors
| Competitor | Differentiation |
|---|---|
| Vapi | Vapi has more provider flexibility; Retell has simpler setup and lower base pricing |
| ElevenLabs | ElevenLabs has superior voices and turn-taking; Retell is more affordable and phone-focused |
| LiveKit Agents | LiveKit is open-source framework; Retell is managed platform with no-code option |
| Dialora, Synthflow | Similar positioning; Retell emphasizes transparency and enterprise reliability |
When to Choose Retell AI
- Choose Retell when: You want transparent pricing, no-code builder, or phone-focused automation
- Choose Vapi when: You need more provider flexibility
- Choose ElevenLabs when: Voice quality is paramount
- Choose LiveKit when: You want open-source control
Ideal Customer Profile
Best fit:
- Call centers automating inbound/outbound calls
- Sales teams doing outbound campaigns
- Customer support automation
- Non-technical teams wanting no-code setup
- Organizations prioritizing cost transparency
Poor fit:
- Web/mobile voice agent use cases
- Applications requiring premium voice quality
- Teams wanting maximum provider flexibility
- Use cases needing sophisticated turn-taking
Viability Assessment
| Factor | Assessment |
|---|---|
| Financial Health | Moderate — $5.1M raised, YC backing |
| Market Position | Growing — Strong in call center automation |
| Innovation Pace | Good — Regular feature updates |
| Ecosystem | Moderate — Good docs, CRM integrations |
| Long-term Outlook | Positive — Clear niche in phone automation |
Bottom Line
Retell AI is the best choice for teams wanting transparent, predictable pricing for phone call automation. The combination of no-code builder and full API makes it accessible to both non-technical users and developers. The $0.07/minute starting price and modular component visibility differentiate it from competitors with hidden fees.
The trade-off is a narrower focus (phone-first) and smaller funding compared to alternatives like Vapi or ElevenLabs. For call center automation with cost transparency, Retell is an excellent choice. For web/mobile voice agents or premium voice quality, alternatives may be better fits.
Recommended for: Call centers, sales teams, and organizations wanting transparent pricing and no-code voice agent setup for phone automation.
Not recommended for: Web/mobile voice agents, applications requiring premium voice quality, or teams needing maximum provider flexibility.
Research by Ry Walker Research