Cartesia

Ultra-low-latency voice AI for developers: Sonic TTS, cloning, and real-time voice agents

★★★★½4.5(310 reviews)

Freemium

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About Cartesia

Cartesia is what AI voice looks like when it's built for the conversation loop rather than the recording booth. Founded by the researchers behind state-space models, its bet is that voice AI's next act is real-time — agents that listen, think, and answer with human-conversation latency — and every product decision follows: Sonic TTS optimized for streaming speed, Ink speech-to-text closing the loop, and Line packaging it into deployable voice agents.

The pricing tells the same story. Credits meter usage like infrastructure, seats are unlimited on every tier, and the commercial license arrives at $5/month — a deliberate contrast with per-seat studio pricing elsewhere in the category. For a developer adding voice to a product, the distance from curiosity to production is one credit card and an afternoon.

The boundaries are the mirror image of Murf's: there's no timeline editor for narrated videos, no course-production workflow, and the stock voice library is leaner than ElevenLabs' community marketplace. Cartesia wins where milliseconds matter — support lines, in-app assistants, interactive experiences — and with teams that want the full voice loop from one API instead of stitching three vendors together.

Key Features

Sonic TTS engineered for ultra-low latency streaming

Line: infrastructure for building production voice agents

Ink speech-to-text for the full listen-think-speak loop

Instant voice cloning from Pro; professional cloning from Startup

Commercial license at a $5/month entry point

Unlimited workspace seats and voice slots on every plan

Credit metering across TTS and agent minutes

Enterprise compliance: DPAs, BAAs, SSO

Pricing Plans

Estimate this tool in your stack

Cartesia prices like an API company: credits metered against usage, with unlimited workspace seats and voice slots on every plan. Free includes 20K credits (about 27 minutes of TTS) for evaluation. Pro at $5/month covers 100K credits (~133 minutes) and unlocks the commercial license and instant voice cloning — one of the lowest commercial entry points in AI voice. Startup at $49/month provides 1.25M credits (~1,667 minutes) plus professional voice cloning and organization features, and Scale at $299/month reaches 8M credits (~10,667 minutes) with high concurrency and priority support. Enterprise adds custom limits, compliance paperwork (DPAs/BAAs), and SSO. The practical read: the $5 commercial entry makes Cartesia the easiest serious TTS to adopt, but the real buyers are voice-agent builders, where latency and concurrency — not price per minute — decide the platform. Credits meter both TTS and agent minutes, so model your call volumes before picking a tier.

Free

20K credits (~27 TTS minutes)
Sonic TTS and Ink speech-to-text
Evaluation use

Pro

$5/mo

100K credits (~133 TTS minutes)
Commercial license
Instant voice cloning
Unlimited seats and voice slots

Startup

$49/mo

1.25M credits (~1,667 TTS minutes)
Professional voice cloning
Organizations and team features

Scale

$299/mo

8M credits (~10,667 TTS minutes)
High concurrency
Priority support

Enterprise

Custom

Custom limits and pricing
DPAs and BAAs for compliance
SSO

Use Cases

Real-time voice agents for support lines and phone automationConversational AI features inside apps needing sub-second responsesProgrammatic narration and TTS at API scaleVoice cloning for consistent product and brand voicesTranscription plus synthesis in one vendor for voice loopsLatency-sensitive gaming and interactive experiences

Limitations

Developer-first: no content studio like Murf for narrated video production
Smaller voice marketplace than ElevenLabs' community library
Credit math across TTS and agent minutes takes estimation
Younger brand competing against entrenched voice incumbents

Frequently Asked Questions

Cartesia or ElevenLabs — which for developers?

Both are strong API platforms. Cartesia's edge is latency and the agent stack — Sonic streams fast enough for natural real-time conversation, and Line packages the agent infrastructure — plus a $5 commercial entry. ElevenLabs counters with the larger voice library, broader ecosystem, and arguably the most expressive stock voices. Latency-critical agent builders lean Cartesia; content-oriented and voice-variety needs lean ElevenLabs.

What can I actually build on the $5 Pro plan?

Pro includes the commercial license, instant voice cloning, and ~133 minutes of TTS monthly — enough for a production feature with modest volume, like narrating dynamic content or a low-traffic voice interface. Real agent deployments with meaningful call volume outgrow it quickly and land on Startup or Scale.

What are Sonic, Ink, and Line?

Cartesia's three products: Sonic is the low-latency text-to-speech engine, Ink is speech-to-text, and Line is the platform for building and running voice agents. Together they cover the full listen-think-speak loop from one vendor, which simplifies real-time voice architectures.

Benchmark Position

Cartesia currently ranks #2 in the ai video leaders scorecard.

View all benchmark scorecards

Benchmark Scorecard

AI Video Leaders

Tools ranked for production depth, platform reach, pricing, and momentum.

View full benchmark

Top Overall

Murf AI76

Best overall balance of value, freshness, capability breadth, and market signal.

Budget Pick

Murf AI82

freemium access and a strong value score for recurring spend.

Power Pick

Murf AI73

High feature depth with strong API/platform support for demanding teams.

Rising Pick

Cartesia73

Strong recent momentum driven by freshness and external trend signals.

Current leaders

avatar video • voice generation • multilingual production

1Murf AI

Value 86 • Feature depth 84 • Trend 63

overall

2Cartesia

Value 86 • Feature depth 84 • Trend 69

overall

3Runway

Value 92 • Feature depth 76 • Trend 73

overall

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