Japanese speech-to-text API
STT API for real-time and async Japanese transcription in voice agents, dictation, and meeting notes. With speaker diarization, end-of-turn detection, and mid-sentence code-switching between Japanese and 60+ other supported languages.
$0.10/hour async · $0.12/hour real-time
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Japanese speech recognition for production voice apps
Japanese is spoken by more than 125 million people in Japan and around the world. If your voice agent, dictation app, or meeting notetaker serves them, speech-to-text has to handle Japanese the way people actually speak it: regional accents, speakers who switch to English mid-sentence, and names, numbers, and IDs that have to come out exactly right.
Soniox STT transcribes Japanese with native-speaker accuracy in real time over a WebSocket or asynchronously from recorded files, through one multilingual API built for 60+ languages. It follows speakers into other languages, labels who said what, and returns timestamps. Transcription biasing toward Japanese is available through the language hints option.
Japanese native-speaker accuracy
Accurate Japanese speech recognition across accents, dialects, and real-world conversational speech.
“We tried a dozen speech-to-text and translation services. Soniox is the best, so that's what we use.”
Cayden Pierce, CEO/CTO at MentraAutomatically detect and switch languages with Japanese
Soniox identifies the language automatically and follows changes between Japanese and other languages live, even within the same sentence.
Get every character right in Japanese
Names, phone numbers, addresses, IDs, serial numbers, and other structured information spoken in Japanese are recognized precisely.
Phone number
私の番号は+49 172 684 9317です。
Reference ID
案件番号はAX-4927-Bです。
Mixed alphanumeric
デバイスのシリアル番号はXR8Q-19F2です。
International name
Nguyễn Minh Anhさんは3時に会議に参加します。
Improve Japanese accuracy with context
Provide terminology, names, or custom vocabulary to guide Japanese recognition toward the right words, without retraining models.
Know when the speaker is finished
Soniox detects when a Japanese speaker has actually completed their thought, not just when they pause.
Know who said what in Japanese
Soniox separates Japanese speakers in real time, so every word stays connected to the person who said it.
Estimate your Japanese speech-to-text API cost
Choose real-time or async transcription and set your monthly audio volume to estimate your Soniox API cost.
Pricing calculator
Japanese speech-to-text API pricing
1,000 hours of audio / month
Pricing assumptions
Based on public pay-as-you-go pricing. Enterprise discounts and committed-use contracts may differ. Some providers charge separately for certain features. The calculator uses the public price for the provider configuration that most closely matches Soniox.
Speech infrastructure for massive scale
Build on one API and deploy in your region
Use the same models and API everywhere, with in-region processing to meet latency, data residency, and regulatory requirements.
Available: US, EU, Japan, India
Coming soon: Korea, Australia, Canada, Saudi Arabia, UK, Brazil
Run mission-critical systems with confidence
- 99.9% uptime
Production-hardened infrastructure with monitoring and redundancy. - low-latency streaming
Process speech in real time with low latency for responsive voice applications. - Priority support
Severity-based incident response with direct access to the Soniox team.
"Before Soniox, our international users always had a noticeably different experience. Now accuracy and responsiveness match across all regions…it feels like one system instead of five."
Alon Yair CTO of Onvego
Japanese speech-to-text use cases
Soniox is built for Japanese voice applications where accuracy, latency, and reliability matter at scale.
Voice agents
Streaming Japanese recognition that knows when the speaker has finished, so agents reply at the right moment.
Voice dictation
Real-time Japanese dictation that writes names, numbers, and codes exactly as spoken.
Meeting notes
Japanese meeting transcripts with speaker labels and timestamps, ready for summaries.
Call center
Real-time transcription, agent assist, and searchable records for every Japanese customer interaction.
Medical transcription
Transcription of Japanese clinical speech, including specialist terminology and patient documentation.
Speech translation
Real-time or async translation of spoken Japanese into 60+ languages.
Start transcribing Japanese speech from $0.10 per hour of audio.
Use Soniox in popular frameworks
Soniox integrates seamlessly with leading real-time communication platforms, AI frameworks, automation tools, and developer SDKs.
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Twilio is a cloud-based customer engagement platform (CPaaS) that provides APIs, allowing developers to integrate voice, messaging (SMS, WhatsApp), email, and authentication capabilities into applications.
Open-source development framework designed to build applications powered by large language models (LLMs).
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Open-source AI SDK with a unified interface across multiple providers. No vendor lock-in, no proprietary formats.
n8n is a powerful, low-code/pro-code workflow automation tool that connects various applications, APIs, and databases to automate tasks.
Build the next generation of voice products, from agents and wearables to dictation, translation, and real-time multilingual experiences.
Go global with one API
Get production-ready speech-to-text recognition, transcription, and translation in 60+ languages.
Also for Japanese: Japanese text-to-speech API for voice output, and the Japanese voice AI platform for enterprise deployment.
Privacy and compliance, built right in
Never stored, never saved.
Audio stays in memory, everything is processed in real-time.
Built for privacy-critical use cases.
Adhering to leading global security, privacy, and compliance standards.
Trusted where privacy matters most.
Used in industries where speech is sensitive, from healthcare to enterprise.
Frequently asked questions
Does Soniox support real-time speech-to-text for Japanese?
How accurate is Soniox for Japanese?
How much does the Japanese speech-to-text API cost?
Which SDKs can I use?
Can Soniox handle mixed-language speech involving Japanese?
Does Soniox support real-time translation from and to Japanese?
Can Soniox recognize numbers, names, and alphanumerics in Japanese?
Does Soniox support speaker diarization in Japanese?
Can I improve accuracy for domain-specific Japanese audio?
Where is Japanese speech data processed, and is it used for training?
Is Soniox ready for production Japanese workloads?
How do I get started?
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