Cartesia vs Amazon Polly
Comparing Cartesia and Amazon Polly Voice Models. Discover the differences in features, pricing, and performance.
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Comparing Cartesia and Amazon Polly Voice Models
Cartesia offers ultra-fast voice generation at 40ms latency, ultra-realistic voices with no hallucinations, and infinite character limits. In contrast, the other option has a higher latency and limited character requests.
Updated on:
Feb 14, 2025
Features
Cartesia
40ms for the Sonic Turbo model, 90ms for the Sonic 2 model
Consistently rated as more natural, expressive, and realistic in blinded human evaluations
Infinite request length
Requires 3 seconds of audio
IPA support with strong contextual understanding
Slider control for speed and emotion + synthetic voice mixing and design
8kHz audio, telephony optimized voices
Supports both on-prem and on-device deployments
15 languages with extensive dialect coverage
Up to 15 on highest self-serve tier (60 parallel conversations), custom for enterprise
Amazon Polly
100ms – 500ms + network time
Less depth and reliability ratings in human evals
Limited character count for longer texts
Not supported
Not supported
IPA support, isolated pronunciation
Stability, similarity, and style exaggeration controls
8kHz audio
No on-device or on-prem support
29
Up to 18 concurrent
Cartesia - Advanced AI Voice Capabilities
Cartesia AI offers the fastest voice model with hallucination-free, ultra-realistic voice generation and cloning.
Low Latency Performance
Cartesia's Sonic model boasts a low latency of 135ms, ensuring real-time interactions.
High-Quality Voice Cloning
Instantly clone voices with just 3 seconds of audio, delivering high-fidelity results.
Ultra-Realistic Voices
Cartesia provides lifelike voices that are nearly indistinguishable from human speech.
Enterprise Ready
Enterprise-grade reliability with 99.9% uptime, SOC2 compliance, and full on-premises support.
Voice Quality Comparison
In evaluating voice quality, Cartesia consistently outperforms Amazon Polly. Cartesia's Sonic model has received a score of 4.7 in independent evaluations, while Amazon Polly scored 4.38. This difference highlights Cartesia's superior naturalness and emotional sensitivity in voice output. Furthermore, Cartesia's voices are designed to be nearly indistinguishable from human speech, providing a more engaging experience for users. This commitment to quality makes Cartesia a preferred choice for applications requiring lifelike voice interactions.
Latency Performance Test
Latency is crucial for real-time applications. Cartesia measures latency using the Time to First Audio (TTFA) metric, achieving a remarkable TTFA of 199 ms. In comparison, Amazon Polly's latency is significantly higher, at 300 ms. This efficiency is due to Cartesia's innovative State Space Models (SSMs), which optimize performance far beyond traditional transformer architectures. The low latency of Cartesia's Sonic model ensures that users experience seamless interactions, making it ideal for applications like customer support and gaming.
Hallucination Rate Analysis
Cartesia stands out with its no hallucination feature, ensuring that voice outputs are accurate and authentic. This is achieved through advanced AI voice cloning technology that eliminates errors and maintains clarity. In contrast, Amazon Polly may experience occasional inaccuracies in voice generation. Cartesia's commitment to delivering crystal-clear audio enhances user trust and satisfaction, making it a reliable choice for applications that require high fidelity in voice outputs.
Voice Cloning Showdown
When it comes to voice cloning, Cartesia excels with its ability to create an instant clone from just 3 seconds of audio. In contrast, Amazon Polly has restrictions on cloning capabilities, requiring longer audio samples. Cartesia's advanced embedding technology ensures high-quality voice replication, maintaining accents and voice quality even in noisy conditions. Additionally, Cartesia's voice mixing and design features provide a wider variety of voices, making it a superior choice for diverse applications.
Voice Design Controllability
Cartesia offers unique voice design controllability features, including emotion and speed modulation, allowing users to create refined voice adjustments that sound natural. This capability enables users to localize voices to match different accents, enhancing the overall user experience. In contrast, Amazon Polly provides limited control options, focusing mainly on stability and similarity without the nuanced adjustments available in Cartesia's offerings. This flexibility makes Cartesia a more versatile tool for developers and content creators.
Pricing Comparison for Cartesia and Amazon Polly
Cartesia
Free - $0 per month with 10k free credits
Pro - $5 per month with 100k credits
Startup - $49 per month with 1.25M credits
Scale - $299 per month with 8M credits
Enterprise - trusted by Fortune 500 companies
Amazon Polly
Standard voices priced at $4.00 per 1 million characters
Neural voices priced at $16.00 per 1 million characters
Long-Form voices priced at $100.00 per 1 million characters
Generative voices priced at $30 per 1 million characters
Custom pricing based on usage and requirements
What Cartesia Customers Say
Join the growing list of companies opting for Sonic.
"Cartesia’s voice API power dynamic and empathetic conversational experiences that are consistently dependable. What really stands out to me is how natural and considerate the responses feel—especially the empathetic tone in statements like ‘I’m sorry, that must be frustrating.’"
Sami Ghoche, CEO of Forethought
"In 1999, Salesforce brought software to the cloud. In 2025, 11x is killing software as we know it and unleashing the era of digital workers. To realise this vision, we needed AI voice technology that feels truly human. Cartesia’s technology gives our AI digital workers reps the speed, reliability, and natural expressiveness required to engage customers at scale.
It's the only solution fit for our relentless drive toward innovation.”
Keith Fearon, Head of Product & Growth, 11x
"Before conversational voice models like Cartesia, Thoughtly relied on legacy text-to-speech APIs from major cloud providers. Nearly two years later, the evolution of this technology is staggering—customers can clone their voice and hear it speaking autonomously over the phone in just 60 seconds.”
Torrey Leonard, CEO, Thoughtly
