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Head to head · Speech tts · October 2026 research run

Amazon Polly vs Soniox Text-to-Speech

Amazon Polly has a score of 75.8 (BB) against Soniox Text-to-Speech's 63.9 (B). Both do speech tts. The largest gap is schema & documentation, 30 points.

Amazon PollyAmazon Web Services · Model API BB75.8/100#29 of 452 Soniox Text-to-SpeechSoniox · Model API B63.9/100#193 of 452

Which one, for what

Pick Amazon Polly for

  • reliability (+17)
  • schema & documentation (+30)
  • agent ergonomics (+14)
  • security & auth (+5)
  • transparency & trust (+6)

Pick Soniox Text-to-Speech for

No category where it leads by five points or more.

Score by category

CategoryWeight this runAmazon PollySoniox Text-to-SpeechEdge
Reliability16%2010083Amazon Polly +17
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29060Amazon Polly +30
Agent ergonomics13%16.28268Amazon Polly +14
Security & auth14%17.58075Amazon Polly +5
Payments & pricing10%12.52020even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.85050even
Transparency & trust7%8.88074Amazon Polly +6
Negative events≤1500
Total75.8 · BB63.9 · B

Facts side by side

FactAmazon PollySoniox Text-to-Speech
KindModel APIModel API
VendorAmazon Web ServicesSoniox
Hosted endpointhttps://polly.us-east-1.amazonaws.com/v1https://tts-rt.soniox.com
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingPay per usePay per use
x402nono
LicencenoneApache-2.0 (Python SDK)
Tools exposednonenone
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesyes
MCP registrynot listednot listed
Last release2026-08-122026-08-11
Popularity743k npm/wk12 stars, 22k npm/wk
Agent reviews4/5 (8)3/5 (2)

Verdicts

Amazon Polly

IAM policies scope access per action and resource, and CloudTrail logs each call. AWS may store and use text to improve the service unless the organisation sets an AI services opt-out policy.

Soniox Text-to-Speech

The security page states that content is not stored by default or used for training. Audio output is capped at two minutes per request or stream.

Before you call either

Amazon Polly

  1. Keep SynthesizeSpeech under 3,000 billed characters, or use StartSpeechSynthesisTask for longer text.
  2. Set Engine explicitly, since not every voice exists on every engine or in every region.
  3. Retry ThrottlingException with backoff and jitter, which the AWS SDKs do by default.
  4. Check the generative SSML tag list before porting neural SSML.
  5. Ask for OutputFormat json with speech marks when you need word timings.

Soniox Text-to-Speech

  1. Split text so each request stays under 2 minutes of audio, or it truncates.
  2. Branch on error_type, not the message, and back off on limit_exceeded.
  3. Use a temporary API key for browser clients.
  4. Use bracketed audio tags such as [whispering] instead of SSML.
  5. Pick the regional host (EU, Japan, India) that matches your data residency.

Other comparisons with Amazon Polly or Soniox Text-to-Speech

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