How to Build an Effective AI Voice Agent: A Step-by-Step Guide

How to Build an Effective AI Voice Agent: A Step-by-Step Guide


AI Voice Agents are gaining popularity as they deliver interactive, conversational experiences over the phone. In fact, the global AI voice market is projected to reach $26.8 billion by 2024, according to MarketsandMarkets. This guide will help you grasp the key components and services needed to build an AI Voice Agent, following the SoftBlues approach.

Voice Streaming via Phone Channel

To start, use Twilio for streaming voice over a phone channel. Twilio provides reliable APIs for voice calling, enabling seamless integration of your Voice AI system with phone networks. This setup guarantees smooth and uninterrupted voice streaming. According to Twilio, their platform handles over 150 billion interactions annually, showcasing its reliability and scalability for businesses of all sizes .

Speech-to-Text Model

To transform spoken words into text, you need a reliable speech-to-text service. High-quality options include OpenAI, Deepgram, and ElevenLabs. Each one balances price and performance effectively, making them suitable choices based on your specific needs and budget.

For instance, Deepgram’s AI-powered platform can handle various accents and languages with high accuracy. Their service processes over 300 million minutes of audio annually and supports over 30 languages and dialects. OpenAI API offers a sophisticated model that can understand context and nuances, making it ideal for more complex conversations. Meanwhile, ElevenLabs provides a user-friendly interface and rapid processing times, ensuring swift and efficient transcription.

Choosing the right service involves evaluating your requirements. If accuracy and language diversity are priorities, Deepgram might be the best fit. For more context-aware processing, OpenAI stands out. If you need quick and straightforward transcription, ElevenLabs offers great functionality.

Using these services will enhance your AI agent’s ability to understand and process conversations, providing a smoother and more intuitive user experience.

AI Agent Backend

The core of your Voice AI system is the AI agent. This agent receives the converted text, understands the user’s intent, and responds appropriately.

There are two main approaches:

  1. Off-the-Shelf Language Model API: Use models like GPT-4 from OpenAI or Google’s offerings. This option is quick and easy, requiring no training on your part.
  2. Language Framework: For more complex needs, use a framework like LangChain. This offers more flexibility and customization but requires more development work.

Text-to-Speech Model

Finally, convert the AI’s responses back into speech. This allows the user to hear the response over the phone.

ElevenLabs excels in voice quality and customization, providing a premier service at a higher price. In contrast, Deepgram’s text-to-speech service balances cost and quality, offering good performance at a more affordable rate. ElevenLabs supports over 50 languages and offers fine-tuning for intonation and emotion, making it ideal for professional use. Meanwhile, Deepgram provides real-time processing and supports multiple languages, proving to be a practical choice for businesses looking to save costs without compromising on voice quality.


Building a Voice AI Agent requires several key components. Twilio facilitates voice streaming, while a reliable speech-to-text model converts voice input. An effective AI agent backend processes the data, and a high-quality text-to-speech model generates responses.

By following the SoftBlues architecture, you can create engaging voice experiences efficiently. This approach saves time and resources, enabling you to focus on enhancing customer interactions over the phone. According to a recent survey, 75% of customers prefer voice interactions for complex queries, emphasizing the importance of a robust Voice AI Agent in today’s market. Start developing your AI Voice Agent today to improve customer satisfaction and streamline communication.

Explore our generative AI consulting services to create a sustainable roadmap for your solution and match our business visions. It’s clear that AI ideas has risks and threats. To exclude a negative experience and rush investments we could test your AI idea before full scale development.

If you’re passionate about creating an AI voice agent to enhance your customer experience, upgrade business automation, and free up your team to solve more complex tasks, click the button below and tell us your use case! Let’s cooperate for your innovative business future.

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