Cartesia vs Vapi

Cartesia — Application · Private · Early-stage · 1 of 1 figure sourced  |  Vapi — Application · Private · Early-stage · 2 of 2 figures sourced

Relationship

Cartesia's customer story says Vapi chose Cartesia as its default text-to-speech provider for voice agents.

1 shared capabilityShared product typeSame scale bandSupplier

1 shared capability — Across all their products, both list voice agent.

Ludbee capability tags · every product each company sells

Shared product type — Both ship agent platform.

Ludbee product records

Same scale band — Both early-stage private.

Ludbee scale bands · from valuation and funding figures

Supplier — “Vapi chooses Cartesia as their default provider for voice agents”

cartesia.ai · checked 2026-10-13

Aligned comparison

FieldCartesiaVapi
StageEarly-stageEarly-stage match
Founded—2020
StatusPrivatePrivate match
CategoryApplicationApplication match
Stack layerAPI service, Agent platformAI agent, Agent platform
HeadquartersSan Francisco, USASan Francisco, USA match

Capability overlap

Shared · 1

Voice agent

Not verified for Vapi · 2

Speech to textText to speech

Recorded for Cartesia. Vapi’s product records say nothing either way — a missing record is not a missing capability.

Not verified for Cartesia · 3

Agent orchestrationEvaluation and observabilityWorkflow automation

Recorded for Vapi. Cartesia’s product records say nothing either way — a missing record is not a missing capability.

Products, side by side

Hand-checked pairing

Cartesia

Agent platform

Managed AgentsAgent platform

Cartesia's managed platform for building and running realtime voice agents: Ink speech-to-text, an LLM you choose and Sonic text-to-speech, with turn-taking, tool calling, telephony (SIP trunking) and built-in evaluations handled by the platform.

Vapi

Agent platform

VapiAgent platform

Developer platform and API for building voice agents that handle phone and web calls: configure the voice, model and telephony, then test, deploy and monitor them.

No counterpart

Cartesia sells these in a stack layer with no product recorded for Vapi yet — nothing on the other side to compare them against.

API service

Sonic / InkAPI service

Sonic (text-to-speech) and Ink (speech-to-text) are Cartesia's voice-generation models, sold via API to developers and enterprises building voice agents.

Vapi sells these in a stack layer with no product recorded for Cartesia yet — nothing on the other side to compare them against.

AI agent

ComposerAI agent

Composer builds and configures voice AI agents through natural conversation.

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