Cartesia Sonic
Sonic is the fastest human-like voice API.
Vapi
Voice AI for developers
Updated February 2026
| Cartesia Sonic | Vapi | |
|---|---|---|
| Rating | 5.0★ | 4.9★ |
| Reviews | 15 | 23 |
| Pros | 4 | 17 |
| FactScore™ | 60.2 | 67.8 |
FactScore™ Comparison
FactScore™ weighs both quality (rating) and popularity (reviews) for a fairer ranking than stars alone.
Pros & Cons
Only in Cartesia Sonic — Pros
Fast performance Real-time voice experiences Ease of use Diverse voice libraryBoth tools — Pros
—Only in Vapi — Pros
Voice AI capabilities Developer-friendly Easy integration Excellent customer support Detailed reports Fast deployment Natural voice quality Orchestration Rapid improvement Tailored functionalities Affordable Customizability Good documentation Interruptible responses Real-time audio handling Smooth experience Web SDKOnly in Cartesia Sonic — Cons
—Both tools — Cons
—Only in Vapi — Cons
Voice AI not 100%Details
| Cartesia Sonic | Vapi | |
|---|---|---|
| Categories | Podcasting Tools, AI Voice Agents, Text-to-Speech Software | AI Voice Agents, Transcription, AI Voice Agent Infrastructure |
| Platforms | Web | Web |
| Became Popular | May 29, 2024 | March 21, 2024 |
| Website | cartesia.ai | vapi.ai |
Who Should Pick Which?
Choose Cartesia Sonic if...
- Fast performance
- Real-time voice experiences
- Ease of use
Choose Vapi if...
- Voice AI capabilities
- Developer-friendly
- Easy integration
With a FactScore™ of 60.2 vs 67.8, Vapi leads in community reception. Cartesia Sonic uniquely offers Fast performance and Real-time voice experiences, while Vapi stands out for Voice AI capabilities and Developer-friendly.
What Users Say
Cartesia Sonic
Cartesia is amazing! They have enabled us to reduce system latency by hundreds of milliseconds – critical to making our conversations feel natural. Their streaming in, streaming out interface, pyth...
Cartesia is a game-changer for us. They provide high-quality voice APIs which are extremely fast and budget-friendly.
Fast, high-quality voice models in multiple languages. Great team and great product velocity.
Vapi
I genuinely love Vapi. The platform has been nothing short of amazing! From the start, I've been impressed not only by the intuitive and powerful tools it offers for building voice applications but...
We chose Vapi because the voice quality is incredibly natural and the experience is smooth and intuitive. The orchestration is thoughtfully designed, and it’s truly developer-friendly — making it e...
Vapi serves as an infrastructure layer facilitating voice AI for PaddleBoat. We're grateful for Vapi's role in bringing this technology to fruition.
Related Comparisons
Frequently Asked Questions
Which is better, Cartesia Sonic or Vapi?
Based on FactScore™, Vapi leads with a score of 67.8 vs 60.2. Vapi has a higher rating of 4.9★ compared to 5.0★.
What are the pros of Cartesia Sonic compared to Vapi?
Cartesia Sonic uniquely offers: Fast performance, Real-time voice experiences, Ease of use, Diverse voice library.
What are the pros of Vapi compared to Cartesia Sonic?
Vapi uniquely offers: Voice AI capabilities, Developer-friendly, Easy integration, Excellent customer support, Detailed reports.
Is Cartesia Sonic better rated than Vapi?
Cartesia Sonic is rated 5.0★ from 15 reviews. Vapi is rated 4.9★ from 23 reviews.
What is the FactScore™ of Cartesia Sonic and Vapi?
FactScore™ weighs rating and review volume together. Cartesia Sonic scores 60.2 and Vapi scores 67.8.
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