Amazon Polly vs. Azure AI Speech

At a glance

Best for

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

Freelancers
Small and mid-sized
Enterprise

Best for

Best for teams already building on Azure who need transcription, synthesis and translation under one compliance and billing umbrella, including where audio cannot leave their own infrastructure.

Small and mid-sized
Enterprise

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

Full Comparison

Criterion	Amazon Polly	Azure AI Speech
Starting price	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 pay-as-you-go Billed by hours of audio transcribed or translated, characters converted to audio and speaker recognition transactions. The rates on Microsoft's pricing page are rendered per region and currency and are not published as fixed figures, so use the Azure pricing calculator for a quote.
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 F0 tier: 5 audio hours a month of speech to text, 0.5 million neural characters a month of text to speech and 5 audio hours a month of speech translation
Output	Synthesised speech as MP3, Ogg Vorbis or raw PCM, plus Speech Marks metadata	Transcripts, synthesised speech, translated speech and avatar video
API	Yes, the Amazon Polly API through the AWS SDKs and the AWS CLI	Yes, Speech SDK, Speech CLI and REST APIs
Languages	Voices in 42 languages and language variants	100+ languages for captioning; the exact locale list differs per feature
Hosting	Cloud (AWS)	Cloud, containers at the edge, embedded on-device, and sovereign clouds including Azure Government and Azure operated by 21Vianet
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, custom neural voice creates a private voice unique to a brand or product, behind a limited-access application and a code of conduct that requires disclosure and recorded consent from the voice talent
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 transcription of streaming audio, fast transcription of pre-recorded files, batch transcription for large volumes, and Voice Live for live conversational agents
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, speech translation produces real-time speech-to-speech and speech-to-text translation, and can generate translated videos
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	SSML control over pitch, pronunciation, rate and volume, custom speech models trained on acoustic, language and pronunciation data, custom vocabulary, language identification, pronunciation assessment, speaker recognition, and a no-code Speech Studio alongside the SDK, CLI and REST APIs
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	Custom neural voice is a limited-access feature with published transparency notes, a code of conduct, disclosure guidelines and a voice-talent disclosure requirement; containers, embedded speech and sovereign clouds keep audio inside your own boundary
Deployment	Cloud (SaaS), Browser-based	more entries Cloud (SaaS), Browser-based, On-premise
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 Azure AI Speech Free tier, then pay-as-you-go
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 Azure AI Speech Free F0 tier: 5 audio hours a month of speech to text, 0.5 million neural characters a month of text to speech and 5 audio hours a month of speech translation
Deployment Amazon Polly Cloud (SaaS), Browser-based Azure AI Speech Cloud (SaaS), Browser-based, On-premise
Company size Amazon Polly Freelancers, Small and mid-sized, Enterprise Azure AI Speech Small and mid-sized, Enterprise
Hosting Amazon Polly Cloud (AWS) Azure AI Speech Cloud, containers at the edge, embedded on-device, and sovereign clouds including Azure Government and Azure operated by 21Vianet

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

Azure AI Speech

Strengths

One service covers transcription, synthesis, translation, speaker recognition and avatars
Runs in containers at the edge, embedded on-device and in sovereign clouds
Custom neural voice and custom speech models for brand voices and domain vocabulary
Free F0 tier with 5 audio hours and 0.5 million characters a month

Limitations

Pay-as-you-go rates are not published as fixed figures and depend on region and currency
Custom neural voice requires a limited-access application before it can be used
A platform assembled from many services rather than a single endpoint, so setup takes longer
The LLM speech model is still in preview

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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Azure AI Speech

Free (F0) Free 5 audio hours a month of speech to text across standard and custom combined, 0.5 million neural characters a month of text to speech, and 5 audio hours a month of standard speech translation.
Standard (S0) Not stated Pay-as-you-go, charged per hour of audio for real-time, batch, fast and custom transcription, per million characters for neural, neural HD and custom professional voice synthesis, and per audio hour for real-time speech translation. Custom speech training is billed per compute hour and custom model endpoint hosting per model per hour. Microsoft renders the rates per region and currency rather than publishing fixed figures.

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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.

Azure AI Speech

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

Azure AI Speech https://azure.microsoft.com/en-us/products/ai-services/ai-speech · 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.