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AI Voice & Speech Comparison

Amazon Polly vs. Rev

At a glance

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

Rev

Best for

Best for teams who need a transcript accurate enough to be relied on in court or in the record, with a human pass available on top of the machine one.

  • Freelancers
  • Small and mid-sized
  • Enterprise

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

Full Comparison

Criterion Amazon Polly Rev
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, then from $25.49 / seat / month The $25.49 Essentials rate is billed annually at $305.90 a year; paid monthly it is $29.99. Pro is $47.99 billed annually or $59.99 monthly. Human services are bought separately by the minute or page and are pooled across seats at account level. The Rev AI developer platform is billed per hour of audio instead, from $0.10 an hour on Reverb Turbo.
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 plan with 45 AI transcription and caption minutes a month, plus free Rev AI credits worth 5 hours of Reverb transcription
Output Synthesised speech as MP3, Ogg Vorbis or raw PCM, plus Speech Marks metadata Transcripts, captions, subtitles and case documents
API Yes, the Amazon Polly API through the AWS SDKs and the AWS CLI Yes, Rev AI for asynchronous and streaming speech-to-text, plus a human transcription API
Languages Voices in 42 languages and language variants 57+ languages for the Rev AI speech-to-text API; 37+ on the Pro subscription; human captions in English and Spanish and subtitles in 17 languages
Hosting Cloud (AWS) Cloud or on-premises for the Rev AI platform
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 No, Rev works only on incoming speech and does not synthesise or clone voices
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, a streaming speech-to-text API for live audio alongside asynchronous transcription of recorded files; human services are turnaround-based rather than real-time
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 No dubbing or synthesised speech. Translation is text-only, at $0.002 to $0.025 per minute through the API depending on standard or premium, plus human subtitles at $6.49 to $15.99 a minute
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 Transcript editor with clipping, multi-file evidence analysis with citations, image analysis, a document editor exporting to Word and PDF, AI templates for chronologies and affidavits, and API-side custom vocabulary, forced alignment with word-level timestamps, topic extraction and sentiment analysis
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 SOC 2, HIPAA, GDPR and PCI compliant with data encrypted at rest and in transit, a stated 99.99% uptime, and on-premises deployment for the API; the Unlimited subscription adds HIPAA and CJIS compliance, SSO and a dedicated specialist
Deployment Cloud (SaaS), Browser-based more entries Cloud (SaaS), Browser-based, On-premise
Onboarding Documentation and knowledge base Documentation and knowledge base
Company size Freelancers, Small and mid-sized, Enterprise Freelancers, Small and mid-sized, Enterprise
Integrations Not stated Clio

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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 Rev Free tier, then from $25.49 / seat / 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 Rev Free plan with 45 AI transcription and caption minutes a month, plus free Rev AI credits worth 5 hours of Reverb transcription
  • Deployment Amazon Polly Cloud (SaaS), Browser-based Rev Cloud (SaaS), Browser-based, On-premise
  • Hosting Amazon Polly Cloud (AWS) Rev Cloud or on-premises for the Rev AI platform
  • Languages Amazon Polly Voices in 42 languages and language variants Rev 57+ languages for the Rev AI speech-to-text API; 37+ on the Pro subscription; human captions in English and Spanish and subtitles in 17 languages

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

Rev

Strengths

  • Human transcription at a stated 99%+ accuracy alongside the machine tier
  • Developer API priced per hour of audio, from $0.10 on Reverb Turbo
  • Runs on-premises as well as in the cloud on the API side
  • Free credits worth 5 hours of transcription, with no card required

Limitations

  • Speech-to-text only, no text-to-speech, dubbing or voice cloning
  • The subscription is built around legal and investigative work, which is dead weight for other uses
  • The free plan covers 45 minutes a month and English only
  • Human services are charged on top of the subscription rather than included

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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Rev

  • Free $0 45 AI transcription and caption minutes a month, English only, up to 5 files analysed at once, document editor and mobile app.
  • Essentials $25.49 Per seat per month billed annually at $305.90, or $29.99 billed monthly. Up to 3 seats, 5,000 AI minutes per seat per month in English and Spanish, up to 10 files analysed and 10% off human services.
  • Pro $47.99 Per seat per month billed annually at $575.88, or $59.99 billed monthly. Up to 5 seats, 10,000 AI minutes per seat per month across 37+ languages, up to 50 files analysed, image analysis, Clio integration and 15% off human services.
  • Unlimited Not stated Custom pricing. Unlimited seats and AI minutes, up to 500 files analysed, HIPAA and CJIS compliance, SSO and a dedicated specialist.
  • Rev AI pay-as-you-go $0.10 Per hour of audio on Reverb Turbo; Reverb is $0.20 an hour and foreign-language transcription $0.30 an hour across 56+ languages. Whisper Fusion and Large are $0.005 a minute. Human transcription through the API is $1.99 a minute. Insights are priced separately: language identification and forced alignment $0.003 a minute, topic extraction and sentiment analysis $0.0008 per 10 words, translation $0.002 to $0.025 a minute. Free credits equivalent to 5 hours of Reverb transcription to start.
  • Human services From $1.99 Per minute for human transcription and for human captions, with up to 15% off on a subscription. Legal rough drafts are $2.25 a page and legal premium transcripts $2.50 a page. Global subtitles run $6.49 to $15.99 a minute depending on the language, across 17 languages.
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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.

Rev

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

Where this comes from

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

Rev https://www.rev.com · checked against the official source on 2026-09-04

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