Cartesia vs Rime (2026)

Managed Agents take webhook tools, where Cartesia sends the HTTPS request to an endpoint the customer exposes, client tools that run in the customer's app over the WebSocket, and system tools for ending a call, sending DTMF and transferring to a phone number, up to 32 tools per agent, so an agent can look up an order or trigger an action during a call. Plugins for LiveKit, Pipecat and other voice stacks distribute Cartesia's models and are not agent integrations.

SourceCartesia, docs.cartesia.ai (Tools, Webhook tools, Integrations)read 2026-09-27

Voice agent stacks call Rime as a text to speech API. It makes no tool calls and takes no action in outside systems. Its integrations with LiveKit, Pipecat, Daily, Vapi, VideoSDK and Twilio plug Rime's voice into those platforms.

SourceRime, docs.rime.ai (llms.txt, integration guides)read 2026-09-27

Cartesia runs a fixed agent loop. A Managed Agent combines Ink-2 listening, the chosen LLM and Sonic speech with turn taking, interruptions and tool calls, and each configuration change is saved as a version. No workflow graph, branching model or hand off between agents is described for Managed Agents, and the older Line SDK is being migrated away from.

SourceCartesia, docs.cartesia.ai (Managed Agents, Agent configuration, Migrate from the Line SDK)read 2026-09-27

Each request turns text into speech, and Rime has no workflow model. In the voice agent tutorials, the listen, think and speak loop runs in the customer's own code or in LiveKit or Pipecat. Orchestration lives in the platform that calls Rime.

SourceRime, docs.rime.ai (Build a voice agent, Streaming TTS)read 2026-09-27

A call batch stores up to 5,000 recipients, and Cartesia dials them in the background, at a scheduled_at time when one is set, up to a concurrency limit, with retries for failed calls. Agents also take inbound and outbound calls on Cartesia or Twilio numbers and SIP trunks, and stream over a WebSocket from web and mobile apps.

SourceCartesia, docs.cartesia.ai (Batch calling, Phone numbers, WebSocket API)read 2026-09-27

The customer's application starts every synthesis by sending a request over HTTP or WebSockets, and Rime runs only when called. It owns no phone numbers, channels, schedules or events. Twilio and the voice platforms supply the calls.

SourceRime, docs.rime.ai (Streaming TTS, WebSocket API)read 2026-09-27

Documents uploaded through the Playground or the documents API, singly or in bulk up to 100 a request, are indexed automatically on upload and organized into nested folders with metadata for filtering. An agent's queries search only the folders attached to it, and documents can be updated or deleted through the API.

SourceCartesia, docs.cartesia.ai (Knowledge Base, Create Document API)read 2026-09-27

There is no retrieval over the customer's content. The product covers models, voices, pronunciation, streaming and on premise engines. The pronunciation dictionary shapes how words are spoken.

SourceRime, docs.rime.ai (llms.txt, Pronunciation control)read 2026-09-27

Within a call the agent keeps the conversation, and dynamic variables set at the start or changed by tools are read by the agent each time it responds. Nothing carries into the next call except what the customer passes in as variables, and no memory layer with a scope and lifetime is described.

SourceCartesia, docs.cartesia.ai (Agent configuration, Dynamic variables)read 2026-09-27

Synthesis is stateless, and each request stands alone. By default Rime collects only character counts and keeps no customer content. It holds no conversation state.

SourceRime, docs.rime.ai (Privacy and compliance)read 2026-09-27

The transfer system tool hands the caller to a phone number, and turn settings end or check in on silent calls. The configuration's Guardrails are rules written into the agent's instructions, and no approval step holds a tool call for a person.

SourceCartesia, docs.cartesia.ai (Agent configuration, System tools)read 2026-09-27

Rime takes no actions, so there is nothing for a person to approve or constrain. Pronunciation control and the spell function govern how text is spoken.

SourceRime, docs.rime.ai (Pronunciation control)read 2026-09-27

Enterprise organizations get self serve SSO over SAML or OIDC, configured by an organization admin, and Admin and Member roles, where only admins manage members, invitations and settings. Cartesia states it is SOC 2 Type II certified, a Vanta trust center sits at trust.cartesia.ai, and Zero Data Retention is available on Enterprise.

SourceCartesia, docs.cartesia.ai (Set up SSO, Set up an organization) and cartesia.ai/pricingread 2026-09-27

Teams have Owner and Member roles, and a permission table sets what each can do. Only owners can invite, edit billing, view all API keys, delete others' keys or remove members. Rime holds SOC 2 Type II, and the audit report is available under NDA. It is HIPAA compliant, with a BAA on Enterprise, and publishes a subprocessor list.

SourceRime, docs.rime.ai (Privacy and compliance, Teams) and rime.ai/securityread 2026-09-27

Every call has a transcript with turn level timestamps and call logs with the agent's logging statements, custom events can be recorded, runtime logs are retrievable through the API, and webhooks deliver call and turn events carrying each turn's tool calls, variable updates and speech latency, plus a post call analysis.

SourceCartesia, docs.cartesia.ai (Observability, Get Call Runtime Logs)read 2026-09-27

Character usage shows in the dashboard and the CLI, and the CLI measures time to first byte per endpoint. On premise containers expose health and OpenTelemetry metrics for Prometheus. Reporting is aggregate, with no trace of each run. Rime keeps no request content by default, so there is nothing per request to inspect.

SourceRime, docs.rime.ai (Monitoring and usage, on-prem Metrics)read 2026-09-27

Enterprise customers can use dedicated regional deployments in the United States, European Union, United Kingdom, India and Australia that keep inference traffic in region. The same models and agents run cloud, on premise and on device, and on premise and VPC deployment are arranged through sales.

SourceCartesia, docs.cartesia.ai (Regional endpoints) and cartesia.ai (home, pricing FAQ)read 2026-09-27

Enterprise customers can run a licensed Coda or Mist v3 engine on their own NVIDIA hosts with Docker Compose or Kubernetes. This on premise option is generally available. Synthesis text and audio stay in the deployment, and only aggregate usage counts go to Rime. Plans offer cloud, on premise or VPC deployment. The cloud API has US West and US East endpoints.

SourceRime, docs.rime.ai (On-prem quickstart, Regional endpoints) and rime.ai/pricingread 2026-09-27

The agents API lists public, Cartesia provided agent templates to help a customer get started, but no template or the job it does is named, and there is no whole agent a customer adopts. The voice library, multilingual voices and pinned model snapshots are model assets, not agents.

SourceCartesia, docs.cartesia.ai (List Templates API reference)read 2026-09-27

There are no packaged agents. The voice catalog holds 287 Coda voices plus Mist voices, which set how the model sounds. Voice agent tutorials for Next.js, Vite, Express, Node and FastAPI give developers sample code to build from, as does an MCP tool that generates Pipecat or LiveKit code.

SourceRime, docs.rime.ai (Build a voice agent, Voices)read 2026-09-27

The customer chooses the model. Each agent's config sets the LLM by ID from the list GET /v1/agents/models returns, with provider, average latency and token prices shown, plus temperature and output limits, and changing it creates a new version so candidates can be compared. Cartesia manages the provider accounts, and speech in and out uses Cartesia's own Ink and Sonic models.

SourceCartesia, docs.cartesia.ai (LLMs, Agent configuration)read 2026-09-27

The customer picks among Rime's own speech models. Coda is the default, Mist v3 gives the lowest latency and Mist v2 offers inline pronunciation. Rime is the only provider, and it names no other provider or way to bring your own model.

SourceRime, docs.rime.ai (Models)read 2026-09-27

A versioned REST API, with 214 reference pages and published OpenAPI and AsyncAPI specs, covers text to speech, speech to text, voices and agents, including agents, tools, knowledge base documents, call batches, metrics and webhooks. Official JavaScript and TypeScript and Python SDKs, a CLI, and an MCP server that runs TTS, STT, voices and pronunciation dictionaries sit beside it.

SourceCartesia, docs.cartesia.ai (llms.txt, Client Libraries, MCP)read 2026-09-27

The API covers HTTP, SSE and WebSocket synthesis and a dictionary coverage endpoint, with quickstarts in cURL, Python, JavaScript and TypeScript. A Rime CLI sits beside it, along with a hosted MCP server whose authenticated tools list voices, check the dictionary, normalize text and synthesize speech. On premise engines take HTTP, gRPC or WebSocket.

SourceRime, docs.rime.ai (API reference, MCP Quickstart, Engine protocols)read 2026-09-27

Completed calls are scored with built in metrics, such as call success and speech latency, and with custom LLM as a judge metrics the customer writes and assigns to an agent, with results exportable, so output quality can be tracked over time. There is no fixture or dataset testing before production, quality gate or tuning loop.

SourceCartesia, docs.cartesia.ai (Metrics, Results)read 2026-09-27

The coverage endpoint and its MCP tool report which words in the customer's script are missing from Rime's pronunciation dictionary. The check runs on input text. Rime's latency benchmarks are measurements of its own models. Customers get no way to evaluate agent behavior.

SourceRime, docs.rime.ai (Coverage, Latency)read 2026-09-27

The DTMF system tool presses phone keys, which is not browser or desktop control, and the browser examples stream voice into a web page, the product running in a browser. There is no browser, desktop or computer control.

SourceCartesia, docs.cartesia.ai (llms.txt, System tools)read 2026-09-27

As a speech synthesis API, Rime has no browser, desktop or computer control.

SourceRime, docs.rime.ai (llms.txt)read 2026-09-27