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Voice Agent Platform
Cartesia Line
Managed platform for building and deploying low-latency voice agents with custom reasoning and Cartesia speech models.
Developer API
Gradium
Low-latency text-to-speech, speech-to-text and speech translation APIs from the Kyutai research team.
Highlighted rows differ between these picks
| Attribute | Cartesia Line | Gradium |
|---|---|---|
| Platform type | Voice Agent Platform | Developer API |
| Pricing | Unknown pricing Usage and enterprise pricing; verify Line, speech-model, telephony, and deployment costs | Subscription pricing Free; $13-$1,615/mo credit plans; Enterprise custom |
| Test it | Free trial | Free trial |
| Calls | Inbound, Outbound | — |
| Human handoff | Yes | No |
| Setup difficulty | Technical | Technical |
| Use cases | Custom Voice Apps Customer Support Financial Services Real Time Assistants | Custom Voice Apps Real Time Assistants Content Localization |
| Useful for |
|
|
| Integrations | ||
| Cartesia Ink | — | |
| Cartesia Sonic | — | |
| Custom LLMs | — | |
| Custom API | — | |
| CLI | — | |
| Webhooks | — | |
| LiveKit | — | |
| Pipecat | — | |
| Vapi | — | |
| Python SDK | — | |
| +2 more across these tools — see each profile for the full list. | ||
Platform type
- Cartesia Line
- Voice Agent Platform
- Gradium
- Developer API
Pricing
- Cartesia Line
Unknown pricing
Usage and enterprise pricing; verify Line, speech-model, telephony, and deployment costs
- Gradium
Subscription pricing
Free; $13-$1,615/mo credit plans; Enterprise custom
Test it
- Cartesia Line
- Free trial
- Gradium
- Free trial
Calls
- Cartesia Line
- Inbound, Outbound
- Gradium
- —
Human handoff
- Cartesia Line
- Yes
- Gradium
- No
Setup difficulty
- Cartesia Line
- Technical
- Gradium
- Technical
Use cases
- Cartesia Line
- Custom Voice AppsCustomer SupportFinancial ServicesReal Time Assistants
- Gradium
- Custom Voice AppsReal Time AssistantsContent Localization
Useful for
- Cartesia Line
- • Low-latency voice agents
- • Custom reasoning
- • Managed agent deployment
- • Teams using Cartesia speech models
- Gradium
- • European-language voice agents
- • EU data residency
- • Streaming TTS and STT from one vendor
- • Live speech translation
Integrations
| Cartesia Line | Gradium | |
|---|---|---|
| Cartesia Ink | — | |
| Cartesia Sonic | — | |
| Custom LLMs | — | |
| Custom API | — | |
| CLI | — | |
| Webhooks | — | |
| LiveKit | — | |
| Pipecat | — | |
| Vapi | — | |
| Python SDK | — |
+2 more across these tools — see each profile for the full list.
What would these cost to run?
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