Soniox vs AssemblyAI speech-to-text
Higher accuracy, real-time fluency, and global reach at lower cost.
Developers choose Soniox for global-ready, real-time fluency
AssemblyAI is known for simple APIs, but for speech itself Soniox outperforms, delivering higher accuracy, true real-time streaming, and global coverage in one API.
With Soniox, you can build one app that works for 8 billion people across 60+ languages. Soniox consistently delivers world-class accuracy, faster real-time streaming, speaker detection, and true multilingual coverage.
Cleaner transcripts, zero mistakes
Benchmarks show Soniox at 6.5% WER in English vs 11.1% for AssemblyAI. Less cleanup, more trust.
One API for 60+ languages
Transcription and translation built in, so your app works worldwide without chaining APIs.
Streaming that feels instant
Token-level results in milliseconds make apps fast, fluid, and human — not robotic.
Helping startups and enterprises ship real world voice apps




See the difference for yourself
Don't just take our word for it. Run the same audio through Soniox and AssemblyAI in real time and compare live results, side by side.
This demo isn't pre-recorded. It makes real API calls to AssemblyAI and Soniox in real time, with each service tuned for its best performance. The framework is open source, so you can inspect or run it yourself.
SONIOX VS ASSEMBLYAI AT A GLANCE
The benchmarks back it up
In a 2025 study across 60 languages and real-world YouTube audio, Soniox reached 6.5% WER in English vs 11.1% for AssemblyAI.
View the full benchmark reportFeature | Sonioxstt-rt-v3 | AssemblyAIUniversal |
---|---|---|
open_in_newSingle Multilingual Model | check | close |
open_in_newLanguage Hints | check | close |
open_in_newLanguage Identification | check | close |
open_in_newSpeaker Diarization | check | close |
open_in_newCustomization | check | close |
open_in_newTimestamps | check | check |
open_in_newConfidence Scores | check | check |
open_in_newTranslation One Way | check | close |
open_in_newTranslation Two Way | check | close |
open_in_newEndpoint Detection | check | check |
open_in_newManual Finalization | check | check |
“It just gets the words right — any language, any accent, any context. That’s what accuracy is supposed to look like.”
Tony Wang,
Cofounder & Chief Revenue Officer at Agora
Built for accuracy, speed, and scale
Accuracy you can trust in production.
Soniox consistently delivers top results, with a 6.5% WER in English vs 11.1% for AssemblyAI. That means cleaner transcripts, less post-editing, and apps you can actually trust in production.
AssemblyAI lags behind in accuracy, especially as audio gets more complex.
Global ready in one API.
With Soniox, you don't need to stitch together multiple services. Transcribe and translate in 60+ languages – in real time or async – all from a single API call.
AssemblyAI only handles transcription, so you'll need extra tools for translation or multilingual support.
Speech-to-text with zero delay.
Soniox streams token-by-token in milliseconds, so conversations feel natural and responsive.
AssemblyAI processes in chunks, creating noticeable delays that break the flow of live apps.
Designed for messy, real-world conversations.
Conversations are messy. People interrupt, switch languages, or talk over each other. Soniox detects speakers, identifies language shifts, and supports endpoint detection out of the box.
AssemblyAI doesn't support real-time translation or seamless multilingual detection, leaving you to patch it together yourself.
Pay up to 3x less than AssemblyAI
With Soniox, transcription, streaming, translation, diarization, timestamps, and confidence are all included in one price. AssemblyAI charges more for their flagship Universal models, while their lower-cost Nano models come with tradeoffs in accuracy.
Effective hourly cost
(typical speech)
Soniox
~$0.10/hour (async)
~$0.12/hour (streaming)
AssemblyAI
~$0.27 (universal async), ~$0.15/hr (streaming), ~$0.12/hr (nano async)
Takeaway
Soniox costs up to 3x less than AssemblyAI, while including translation and richer real-time features out of the box. AssemblyAI's cheaper models cut accuracy, while Soniox includes full accuracy and features at one flat rate.
- Soniox bills per token, which works out to the effective hourly rates above for typical conversational speech.
- AssemblyAI pricing varies by model. Nano is cheaper but sacrifices accuracy; Universal is higher accuracy but more expensive.
- All comparisons use publicly listed rates as of 2025.
Fluent at any speed
Watch Soniox keep up with fast speech in any language
Frequently asked questions about Soniox vs AssemblyAI
1.How accurate is AssemblyAI compared to Soniox?arrow_downward
2.Does AssemblyAI support translation?arrow_downward
3.How fast is AssemblyAI's streaming?arrow_downward
4.What about multilingual or messy audio?arrow_downward
5.How does AssemblyAI pricing compare to Soniox?arrow_downward
6.Why is Soniox more cost-efficient?arrow_downward
Soniox surpasses AssemblyAI in any language
Get the most accurate, real-time speech-to-text transcription and translation in 60+ languages
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