AI Voice & Speech Comparison

Amazon Polly vs. Cartesia

At a glance

Amazon Polly

Best for

Best for developers already on AWS who need speech synthesis inside an application, billed per character.

Freelancers
Small and mid-sized
Enterprise

Cartesia

Best for

Best for developers building low-latency, real-time voice agents.

Small and mid-sized
Enterprise

Cataleo does not name a winner. Both statements come from the vendors themselves.

Full Comparison

Criterion	Amazon Polly	Cartesia
Starting price	lower value Free tier, then from $4 per 1 million characters Pay-as-you-go by characters sent for synthesis, including spaces and most SSML tags. Standard $4, Neural $16, Generative $30 and Long-Form $100 per 1 million characters. Speech Marks requests are charged at the same rates.	Free tier; Pro from $5 / month Usage-based credits and agent minutes. Pro adds a commercial-use license and instant voice cloning.
Free trial	AWS Free Tier: 5 million Standard characters a month, plus 1 million Neural, 500,000 Long-Form and 100,000 Generative characters a month for the first 12 months	Free tier with 20,000 credits per month
Commercial use	Not stated	Paid
Output	Synthesised speech as MP3, Ogg Vorbis or raw PCM, plus Speech Marks metadata	Low-latency real-time speech, instant clone from around three seconds
API	Yes, the Amazon Polly API through the AWS SDKs and the AWS CLI	Yes
Hosting	Cloud (AWS)	Not stated
Voice cloning	Brand Voice only, and not as a self-service feature. It is a custom engagement in which the Amazon Polly team builds a Neural voice for the exclusive use of one organisation, covering persona, casting an actor, recording their speech and training the model, after which the voice is released to that customer's AWS account. It starts with an AWS account manager rather than an upload	Yes, instant cloning from around three seconds, plus a Pro clone trained on 30 minutes or more of audio
Real-time use	Yes, the API returns an audio stream that an application can begin playing as it arrives, in near real time, with a choice of sampling rates to trade bandwidth against audio quality	Yes, real-time text-to-speech (Sonic), built for live voice agents
Languages	Voices in 42 languages and language variants, from Arabic and Cantonese to Icelandic and Korean. Which of the four engines a given voice supports differs by voice, and the Generative and Long-Form engines cover far fewer voices than Standard and Neural	Yes, Sonic 3.6 covers 44 languages natively, chosen per request with a language parameter and regional locale variants
Speech-to-speech and dubbing	No. Polly synthesises speech from text and nothing else. Transcription and translation are separate AWS services rather than features of this one	Yes, a voice changer, plus localization that converts existing audio across the 44 supported languages while holding the speaker's emotion and identity
Editing and controls	SSML for phrasing, emphasis, intonation, pitch, rate and volume, custom Amazon SSML tags such as the Newscaster speaking style, custom lexicons that set the pronunciation of particular words through IPA-style phonemes, and Speech Marks metadata for speech-synchronised facial animation or word highlighting	Speed 0.6x to 1.5x, volume 0.5x to 2x, an emotion setting (neutral, calm, angry, content, sad) or model-interpreted emotion, custom pronunciation dictionaries, accent selection for multilingual voices and text normalization
Consent and trust	Brand Voice is a managed engagement rather than an upload, so a custom voice exists only where an actor has been cast and recorded for that purpose, and the finished voice is restricted to the commissioning organisation's AWS account IDs. There is no self-service cloning path that could be pointed at a voice without its owner taking part	The terms of service forbid publishing audio of another person's voice without that person's express permission, and name deceased people and political candidates explicitly
Deployment	Cloud (SaaS), Browser-based	Cloud (SaaS), Browser-based
Onboarding	Documentation and knowledge base	Documentation and knowledge base
Company size	more entries Freelancers, Small and mid-sized, Enterprise	Small and mid-sized, Enterprise

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Row where the values differ The small markers point at the lower number, the longer list or the stated feature. They describe the data, they are not a verdict.

The short version

Key Differences

Starting price Amazon Polly Free tier, then from $4 per 1 million characters Cartesia Free tier; Pro from $5 / month
Free trial Amazon Polly AWS Free Tier: 5 million Standard characters a month, plus 1 million Neural, 500,000 Long-Form and 100,000 Generative characters a month for the first 12 months Cartesia Free tier with 20,000 credits per month
Company size Amazon Polly Freelancers, Small and mid-sized, Enterprise Cartesia Small and mid-sized, Enterprise
Output Amazon Polly Synthesised speech as MP3, Ogg Vorbis or raw PCM, plus Speech Marks metadata Cartesia Low-latency real-time speech, instant clone from around three seconds
API Amazon Polly Yes, the Amazon Polly API through the AWS SDKs and the AWS CLI Cartesia Yes

Every line is one datapoint from the table above, picked automatically. Nothing here is written text.

The trade-offs

Strengths and Limitations

Amazon Polly

Strengths

Four voice engines let quality be traded against cost per character, from $4 to $100 per million
Generous free tier, with 5 million Standard characters a month that does not expire
Generated speech may be cached and replayed at no additional cost
Speech Marks and custom lexicons cover lip-sync and awkward pronunciations properly
Brand Voice cannot be used without the voice owner being cast and recorded

Limitations

Text to speech only: no transcription, translation or dubbing in this service
No self-service voice cloning, and Brand Voice starts with an AWS account manager
The Generative and Long-Form engines cover far fewer voices than Standard and Neural
Long-Form voices cost $100 per million characters, twenty-five times the Standard rate
Useful only from code, so it suits developers rather than anyone wanting an editor

Cartesia

Strengths

Lowest-latency real-time voice for agents
Instant three-second cloning
Cost-effective developer API

Limitations

Less expressive on long-form and audiobook content
Newer and developer-oriented

Plans

Pricing

Amazon Polly

AWS Free Tier Free 5 million Standard characters a month. Neural 1 million, Long-Form 500,000 and Generative 100,000 characters a month for the first 12 months.
Standard voices $4 Per 1 million characters for speech or Speech Marks requests, outside the free tier.
Neural voices $16 Per 1 million characters for speech or Speech Marks requests, outside the free tier.
Generative voices $30 Per 1 million characters for speech requests, outside the free tier.
Long-Form voices $100 Per 1 million characters for speech or Speech Marks requests, outside the free tier.

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Cartesia

Free $0 20,000 credits per month plus $1 of prepaid agent usage. Text-to-speech and speech-to-text.
Pro $5 / month 100,000 credits, a commercial-use license and instant voice cloning.
Startup $49 / month 1.25 million credits, professional voice cloning and organizations.
Scale $299 / month 8 million credits, priority support and high concurrency limits.
Enterprise Not stated Custom credits and agent usage, custom concurrency limits, DPAs/BAAs and SSO.

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What users say

Review Scores · opens after launch

Amazon Polly

Ease of use: Not rated yet
User interface: Not rated yet
Onboarding: Not rated yet
Support and service: Not rated yet
Value for money: Not rated yet
Features: Not rated yet

No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.

Cartesia

Ease of use: Not rated yet
User interface: Not rated yet
Onboarding: Not rated yet
Support and service: Not rated yet
Value for money: Not rated yet
Features: Not rated yet

No reviews yet. Be the first to review this tool. Every review is checked for fairness before it appears, and the vendor cannot have one removed.

Where this comes from

Amazon Polly https://aws.amazon.com/polly/ · checked against the official source on 2026-09-13

Cartesia https://cartesia.ai · no check date recorded yet

This table lists factual criteria taken from information the vendors publish themselves. For how we put it together, see the methodology.