Cartesia
Ultra low latency Sonic TTS, speech to text and voice agent platform built for real time developers.
Best for Developers building real time voice agents
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What it does
Cartesia provides an audio intelligence platform that combines text to speech, speech to text, and voice agents in an API built for real time use. Users can input text or audio streams to generate speech, transcribe conversations, or run full conversational phone agents. It is designed for developers and enterprises building interactive voice applications across industries like finance and healthcare.
Read more: 4 features and how people use themShow less
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Sonic text to speech
Generates realistic spoken audio from text using a dedicated speech synthesis model.
Use caseA developer adds synthesized voice outputs to an application so users can listen to written content spoken aloud.
From cartesia.ai -
Ink speech to text
Transcribes spoken audio into text in real time using a streaming model.
Use caseAn engineering team streams live caller audio into text to transcribe conversations as they happen.
From cartesia.ai -
Managed voice agents
Provides an infrastructure platform with provisioned phone numbers and models to handle incoming and outgoing calls.
Use caseA fraud detection team sets up an automated voice agent to place outbound verification calls on suspicious transactions.
From cartesia.ai -
Pro voice clone
Fine tunes a speech synthesis model on thirty or more minutes of recorded audio to replicate a specific person's accent, style, and tone.
Use caseA customer service team uploads thirty minutes of a spokesperson's clean studio recordings to build a custom branded agent voice.
From docs.cartesia.ai
Written from Cartesia's own website, checked . Each feature links to the page it comes from; images are Cartesia's own.
Every plan
| Plan | Monthly | Billed yearly | Per | What it includes |
|---|---|---|---|---|
| Free | Free | Not listed | per account | 20K credits/mo, no cloning, concurrency 2 TTS |
| Pro | $5 | Not listed | per account | 100K credits/mo, instant voice cloning, commercial use |
| Startup | $49 | Not listed | per account | 1.25M credits/mo, 2 pro voice clone slots |
| Scale | $299 | Not listed | per account | 8M credits/mo, 4 pro voice clone slots, concurrency 15 TTS |
| Enterprise | Contact sales | Not listed | custom | contact sales |
From Cartesia's own pricing page, checked . Prices are in US dollars per month; "billed yearly" is the monthly price when you pay for a year up front. A few figures (often the yearly price) are derived rather than printed on the page.
Before you pay
- Renews automatically
- Yes
- Unused credits roll over
- Partial
- Commercial use
- Paid plans only
- SOC 2
- Yes
- Support
- Email, Slack
What Cartesia says
Email support Reach us at support@cartesia.ai for help with integration, your account, or billing.
Source page
Only what Cartesia's own pages state, with the quote behind each answer. Anything they don't publish is left out rather than guessed.
Getting started with Cartesia
- Create a Cartesia API key and add it to your .bashrc or .zshrc environment file.
- Download and install ffplay from the FFmpeg download page to play audio output.
- Install the Cartesia client library using pip for Python or npm for JavaScript.
- Create a script file that establishes a WebSocket connection, sets up a context, pushes text chunks, and sends no_more_inputs.
- Execute your script with python3 or npx tsx to stream text and listen to the audio output played through ffplay.
Tips
- Use ephemeral access tokens for authentication instead of your API key when accessing the Cartesia API from a browser.
- Do not install the ws package in browser environments when using JavaScript, as the native WebSocket API is sufficient.
- Reuse the assigned agent_id across new conversations instead of creating an agent again.
Written from Cartesia's own help pages: docs.cartesia.ai/get-started/realtime-text-to... · docs.cartesia.ai/agents/introduction
Cartesia video tutorials
Independent creators on YouTube, not Cartesia or us. The video loads from YouTube only when you press play.
What the free plan includes
20K credits/
Questions people ask about Cartesia
How much does Cartesia cost?
Paid plans start at $5 a month (Pro). 5 plans are listed above, from Cartesia's own pricing page.
Is Cartesia free?
Yes, there is a free plan: 20K credits/month, no voice cloning, $1 prepaid agent credit.
Do unused Cartesia credits roll over?
Partly: some unused credits carry over, with limits. Source
Can I use Cartesia output commercially?
Yes, on paid plans only. Source
Does Cartesia have an API?
Yes.
Do TTS, STT, and Agent concurrency limits affect each other?
No, each service has its own dedicated concurrency pool, so using TTS won’t impact your STT or Agent concurrency. Source
What happens to my rollover credits if I change my pricing tier?
You keep all the credits already paid for, and the rollover cap resets to 2x your new monthly plan rate. Source
What if I cancel or downgrade my tier in the middle of a payment period?
You keep the credits in your account until you use them, and your account remains in the same tier until the end of that period. Source
Is Cartesia SOC 2 Type II certified?
Yes, Cartesia is SOC 2 Type II certified. Source
Works with
- AI models
- Sonic 3.5, Sonic 3.6, Ink 2, State Space Models (SSMs), Mamba, H Nets
- Languages
- 40+ languages
Where this came from
Plans, prices and limits were copied from Cartesia's own pages, then checked .
- cartesia.ai/pricing
- cartesia.ai/
- cartesia.ai/pricing
- docs.cartesia.ai/build-with-cartesia/capability-guides/clone-voices-pro
- docs.cartesia.ai/get-started/overview
How we collect prices and rank tools · Is something wrong? Correct this listing
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