Build Real-Time, Multilingual Apps with One STT API

Voice has become the primary input for modern digital interaction. From AI agents managing customer support to hands-free field applications and global customer experiences, the ability to instantly and accurately convert spoken language into text is non-negotiable.

Transcription accuracy is the foundation. If the transcription is incorrect, it can lead to miscommunication, data entry errors, and even compliance issues in industries that depend on precise records.

However, building for this voice-first world is challenging. Product teams and developers constantly face a forced trade-off: Do you prioritize the fastest ASR engine, the most accurate one, or the one with the best language coverage? Achieving all three often requires integrating multiple vendors, leading to complex and expensive architectures.

Today, that trade-off ends.

We are proud to introduce the Telnyx Real-Time Speech-to-Text (STT) API: a single, developer-friendly integration that delivers sub-250ms transcription, 100+ language support, and the combined intelligence of multiple ASR engines.

Want to see it in action? Check out the Telnyx STT API page or contact our team to learn more.

The Vendor Dilemma: Why Multi-Engine Access is Critical

Building a global application that relies on voice means your transcription needs to shift based on the geography, the user's dialect, and the audio quality. Choosing just one vendor means accepting compromises on cost, accuracy, or coverage.

• Some scenarios call for Deepgram Nova for maximum accuracy in specific high-value customer interactions. Others may need Deepgram Flux, as it understands the flow of conversation and detects when someone finishes speaking, interrupts, or needs a response from the AI.
• You may need Google STT for its specialized coverage of certain regional and low-resource languages.It supports over 80 languages and is a reliable general-purpose engine for multilingual deployments at scale.
• For enterprise-ready voice workflows, Azure STT offers stable real-time performance with broad language coverage.
• And for teams looking for fast transcription with built-in language auto-detection, our in-house engine runs on OpenAI Whisper Large-V3-Turbo. Paired with Telnyx’s real-time infrastructure, it delivers sub-250ms latency without compromising on performance.

Each engine excels at something different. That’s why multi-engine access is table stakes for building global voice applications that perform at scale.

The Telnyx Solution: One API for Every Engine

With Telnyx Real-Time STT, you don’t have to choose. Telnyx offers the best ASR providers via a single API. You are no longer forced to decide between vendors optimized for speed and those optimized for language coverage. You access them all through a single Telnyx STT endpoint. This allows your product teams to instantly switch the underlying ASR engine via a single parameter, ensuring you always have the best balance of cost, accuracy, and language support without ever changing your core code.

This flexibility allows you to optimize your solution for every distinct use case, region, or price point, all from one set of documentation.

Performance Engineered for the Enterprise

1. Real-Time Transcription Under 250ms

For live voice applications, latency dictates user experience. A delay of half a second feels unnatural and can break the flow of a customer service call or frustrate a voice-controlled user.

Telnyx delivers ultra-low latency for smooth, real-time transcription. Our globally distributed, private infrastructure and optimized streaming APIs (via WebSocket) keep performance consistent and fast. For critical applications like AI agents and live captioning, we provide near-instant text back in under 250ms, ensuring seamless, natural interactions every time.

2. 100+ Language Coverage and Global Reach

If your app serves a global audience, your STT solution needs to cover that audience effectively. Telnyx is built for the global enterprise, offering support for 100+ languages and regional variants.

This multilingual support is essential for:

• Global Customer Service: Serving users in their native language leads to higher engagement and satisfaction.
• Adaptability: Features like automatic language detection allow your application to instantly adapt to a user's speech without requiring pre-configuration.

3. Enterprise Security and Regional Control

For contact centers, healthcare, and financial services, the security and location of transcription data are critical. Telnyx offers enterprise-grade security and flexible data residency. This includes EU hosting for seamless GDPR compliance and ensuring data remains in-region. Our dedicated infrastructure and strong global network connectivity ensure your data is always protected and compliant with industry standards.

4. The Accuracy Advantage: Built for the Real World

Accuracy is often degraded by challenging acoustic environments and complex language. By providing access to specialized engines like Deepgram Nova-3, we ensure high fidelity for your most demanding applications:

• Noise and Distance: Our platform can handle far-field speech, delivering crystal-clear transcripts even when the speaker is at a distance or in noisy environments (like a drive-thru or busy call center).
• Hyper-Specific Terminology: Our integrated ASR models recognize domain-specific terminology for specialized fields like healthcare, banking, and e-commerce. You can further tune this using custom vocabulary to ensure precise recognition of specific terms and jargon.
• Critical Data Precision: We ensure high accuracy on complex number sequences, such as patient IDs, credit card numbers, or long numeric entities, where any error is unacceptable.

Real-World Applications: Where Ultra-Fast STT Changes the Game

The Telnyx STT API is built for the highest-stakes applications that require both performance and precision:

• Voice-Enabled AI Agents and Assistants: Power real-time speech input for conversational AI, allowing for fast, accurate transcription that keeps dialogues natural and seamless.
• Hands-Free Productivity: Enable voice-driven input for complex workflows, perfect for doctors, drivers, and field technicians who need to capture critical information without manual typing.
• Contact Center Automation: Supports 2-channel call audio and speaker diarization, making it ideal for transcribing customer calls, improving real-time agent assistance, and providing accurate data for post-call analytics.
• Live Transcription and Accessibility: Deliver instant captions and subtitles for virtual meetings, broadcasts, and live events, greatly improving access and engagement for users with hearing impairments or language barriers.
• Custom Vocabulary and Training: Our platform supports engines that allow you to add custom vocabulary or train the system on your specific domain (e.g., industry-specific jargon), ensuring a one-size-fits-all approach doesn't compromise accuracy for your business.

Ready to Add Real-Time STT to Your App?

Voice is rapidly becoming the most natural way to interact with digital products. The Telnyx STT API gives your team a fast, reliable, and developer-friendly way to convert speech into text in real time.

With 100+ language support, sub-250ms latency, flexible ASR engine options, and enterprise-grade security, Telnyx makes it simple to add accurate speech recognition to any workflow or experience.

Sign up for free and get your API key. Check out our transparent pricing and explore dev docs to learn how you can build.