# Assembly AI vs Cartesia: who uses which

On usedby, 49 companies use Assembly AI and 39 use Cartesia. 2 companies use both, including LiveKit and Retell. Counts include every proof level, job-post signals included. Companies named on both have a confirmed or observed line on each side. Latest check 2026-10-08: 86 of 88 public lines checked.

## Side by side

|  | [Assembly AI](https://www.usedby.ai/tools/assembly-ai.md) | [Cartesia](https://www.usedby.ai/tools/cartesia.md) |
|---|---|---|
| Public customers | 49 | 39 |
| Confirmed | 22 | 36 |
| Observed | 27 | 3 |
| Signals (job posts) | 0 | 0 |
| Top industries of customers | Artificial Intelligence (12), Marketing Tech (6), Sales Tech & CRM (5) | Artificial Intelligence (4), DevTools & Infrastructure (2), Sales Tech & CRM (2) |
| Category | Speech & Audio API | Speech & Audio API |
| Security | SOC 2 Type II ([assemblyai.com](https://www.assemblyai.com/security), checked 2026-10-04) | PCI DSS, HIPAA, SOC 2 Type II ([trust.cartesia.ai](https://trust.cartesia.ai/), checked 2026-10-08) |
| Data processing terms | A data processing agreement is available. ([assemblyai.com](https://www.assemblyai.com/legal/privacy-policy), checked 2026-10-04) | A data processing agreement is available. ([cartesia.ai](https://www.cartesia.ai/legal/dpa), checked 2026-10-08) |
| Free trial | — | Free trial or free plan available. ([cartesia.ai](https://www.cartesia.ai/pricing), checked 2026-10-08) |
| Pricing | — | Free: $0 /mo; Pro: $5 /mo; Startup: $49 /mo; Scale: $299 /mo; Enterprise: contact sales ([cartesia.ai](https://www.cartesia.ai/pricing), checked 2026-10-08) |

## Companies named on both

Confirmed or observed on each side.

| Company |
|---|
| [LiveKit](https://www.usedby.ai/companies/livekit.md) |
| [Retell](https://www.usedby.ai/companies/retell.md) |

## Published results

Reviewed stories only; usedby did not measure the figures.

- Assembly AI: [Aloware](https://www.usedby.ai/case-studies/aloware-assembly-ai.md): **50%**: “Aloware has seen 50% of its client base convert to its suite of AI-powered packages” (captured by usedby 2026-10-08)
- Assembly AI: [EchoAI](https://www.usedby.ai/case-studies/echo-ai-assembly-ai.md): **18 million calls**: “the 18 million calls it processes a year” (captured by usedby 2026-10-08)
- Cartesia: [Daily](https://www.usedby.ai/case-studies/daily-cartesia.md): **500ms**: “Daily Bots delivers voice-to-voice latencies – including transport over the network – as fast as 500ms.” (published 2024-09-24)
- Cartesia: [Goodcall](https://www.usedby.ai/case-studies/goodcall-cartesia.md): **90 ms**: “Goodcall achieves a 90 ms on average for time-to-first-audio” (published 2024-10-09)

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Source: https://www.usedby.ai/compare/assembly-ai-vs-cartesia · How we check: https://www.usedby.ai/methodology