Best for
Best for developers building low-latency, real-time voice agents.
- Small and mid-sized
- Enterprise
AI Voice & Speech Comparison
Cartesia vs. Retell AI
At a glance
At a glance
Best for
Best for teams putting AI voice agents on real phone lines and testing them before they meet customers.
- Small and mid-sized
- Enterprise
Cataleo does not name a winner. Both statements come from the vendors themselves.
Full Comparison
| Criterion | Cartesia | Retell AI |
|---|---|---|
| Starting price | Free tier; Pro from $5 / month Usage-based credits and agent minutes. Pro adds a commercial-use license and instant voice cloning. | lower value From $0.07 / minute of calls Pay as you go, quoted by the vendor as $0.07 to $0.31 per minute for voice agents depending on the models, telephony and add-ons chosen, plus from $0.002 per message for chat agents. Enterprise is quoted by sales. |
| Free trial | Free tier with 20,000 credits per month | $10 in free credits, no contract and no commitment; 20 concurrent calls are included |
| Commercial use | Paid | Yes, usage-based |
| Output | Low-latency real-time speech, instant clone from around three seconds | Voice agents for inbound and outbound phone calls and web calls, plus chat agents over SMS and a web widget |
| API | Yes | Yes, REST API with Node.js and Python libraries, webhooks and an MCP server |
| Hosting | Not stated | Cloud on AWS; the vendor states it does not currently operate services within the European Union |
| Voice cloning | Yes, instant cloning from around three seconds, plus a Pro clone trained on 30 minutes or more of audio | Yes, custom voices can be added by searching ElevenLabs community voices, importing an existing clone or training one from uploaded recordings, with Inworld, Cartesia, MiniMax, ElevenLabs and Retell's own platform clones as providers; up to 100 custom voices per account |
| Real-time use | Yes, real-time text-to-speech (Sonic), built for live voice agents | Yes, live inbound and outbound phone calls and browser web calls, with a proprietary turn-taking model, batch calling for campaigns and live monitoring that lets a human listen in or step in |
| Languages | Yes, Sonic 3.6 covers 44 languages natively, chosen per request with a language parameter and regional locale variants | 57 languages are listed for text-to-speech and 55 for speech recognition, and a language needs a provider on both sides to be usable. An agent runs either in a single language or as a multilingual agent across a chosen set |
| Speech-to-speech and dubbing | Yes, a voice changer, plus localization that converts existing audio across the 44 supported languages while holding the speaker's emotion and identity | A call runs as spoken conversation by chaining speech recognition, a language model and text-to-speech; dubbing of existing recordings is not part of the product |
| Editing and controls | Speed 0.6x to 1.5x, volume 0.5x to 2x, an emotion setting (neutral, calm, angry, content, sad) or model-interpreted emotion, custom pronunciation dictionaries, accent selection for multilingual voices and text normalization | Single and multi-prompt agents or node-based conversation flows, knowledge bases, expressive mode for emotion and emphasis, custom pronunciation with IPA, CMU, Pinyin or Jyutping, denoising and interruption sensitivity, voicemail and IVR handling, plus a playground, simulation tests, A/B testing and post-call analysis |
| Consent and trust | The terms of service forbid publishing audio of another person's voice without that person's express permission, and name deceased people and political candidates explicitly | HIPAA compliant, SOC 2 Type 1 and Type 2 certified and GDPR compliant, with a BAA and a DPA including EU standard contractual clauses available for self-signing at no extra fee. Per-agent data retention runs from 1 day to 2 years, PII can be excluded from what is stored, and recording URLs can be signed. Services are not currently operated inside the EU |
| MCP-ready | No | stated Yes |
| Deployment | Cloud (SaaS), Browser-based | Cloud (SaaS), Browser-based |
| Onboarding | Documentation and knowledge base | Documentation and knowledge base |
| Company size | Small and mid-sized, Enterprise | Small and mid-sized, Enterprise |
| Integrations | Not stated | Twilio, Telnyx, Vonage, Genesys Cloud, Five9, Avaya, Amazon Connect, HubSpot, Make, n8n, GoHighLevel |
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The short version
Key Differences
- Starting price Cartesia Free tier; Pro from $5 / month Retell AI From $0.07 / minute of calls
- Free trial Cartesia Free tier with 20,000 credits per month Retell AI $10 in free credits, no contract and no commitment; 20 concurrent calls are included
- MCP-ready Cartesia No Retell AI Yes
- Commercial use Cartesia Paid Retell AI Yes, usage-based
- Output Cartesia Low-latency real-time speech, instant clone from around three seconds Retell AI Voice agents for inbound and outbound phone calls and web calls, plus chat agents over SMS and a web widget
Every line is one datapoint from the table above, picked automatically. Nothing here is written text.
The trade-offs
Strengths and Limitations
Cartesia
Strengths
- Lowest-latency real-time voice for agents
- Instant three-second cloning
- Cost-effective developer API
Limitations
- Less expressive on long-form and audiobook content
- Newer and developer-oriented
Retell AI
Strengths
- Usage-based per-minute pricing with no contract and $10 in free credits to start
- Testing tooling built into the product: playground, simulation runs, batch tests and A/B splits of live traffic
- Custom voices can be cloned or imported across several voice providers
- HIPAA, SOC 2 Type 1 and Type 2 and GDPR, with BAA and DPA available for self-signing at no extra fee
Limitations
- The per-minute rate varies widely with the models, telephony and add-ons chosen, so the entry rate is not the rate to budget with
- The vendor states it does not currently operate services within the European Union
- Retell-managed phone numbers cover the US and Canada only; elsewhere a number has to be brought in
- Building and running an agent assumes developer work; there is no packaged seat-based plan
Plans
Pricing
Cartesia
- Free $0 20,000 credits per month plus $1 of prepaid agent usage. Text-to-speech and speech-to-text.
- Pro $5 / month 100,000 credits, a commercial-use license and instant voice cloning.
- Startup $49 / month 1.25 million credits, professional voice cloning and organizations.
- Scale $299 / month 8 million credits, priority support and high concurrency limits.
- Enterprise Not stated Custom credits and agent usage, custom concurrency limits, DPAs/BAAs and SSO.
Retell AI
- Pay as you go $0.07 Per minute and up, quoted by the vendor as $0.07 to $0.31 per minute for voice agents and from $0.002 per message for chat agents. Includes $10 in free credits and 20 concurrent calls, with no contract.
- Enterprise Not stated Contact sales. Custom pricing for higher volumes, with dedicated support and implementation, custom compliance terms covering HIPAA, SSO and a DPA, no cap on concurrent calls and a dedicated server option.
What users say
Review Scores · opens after launch
Cartesia
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.
Retell AI
- Ease of use
- Not rated yet
- User interface
- Not rated yet
- Onboarding
- Not rated yet
- Support and service
- Not rated yet
- Value for money
- Not rated yet
- Features
- Not rated yet
No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.
Where this comes from
Where this comes from
Cartesia https://cartesia.ai · no check date recorded yet
Retell AI https://www.retellai.com · checked against the official source on 2026-09-13
This table lists factual criteria taken from information the vendors publish themselves. For how we put it together, see the methodology.