What Is PolyAI? A Detailed Guide to Building an AI Voice Assistant

Have you ever waited minutes to reach a call center agent, pressing one menu key after another without getting your problem solved? For businesses, overloaded lines at peak hours, missed after-hours calls and the pressure of answering the same questions over and over are just as hard to solve.

PolyAI was built to change that experience. Instead of a rigid keypad menu, PolyAI uses AI to create voice assistants that can listen, understand and respond as naturally as a real agent, 24/7. Join Aniday as we explore what PolyAI is, who it suits, how much it costs and how to build your first assistant in just a few minutes.

Introduction to PolyAI

1. What is PolyAI?

PolyAI is a conversational voice AI platform that helps businesses build and manage AI customer service assistants. The company was founded in 2017 in London by a research team from the University of Cambridge, with Nikola Mrkšić as co-founder and CEO. In December 2025, PolyAI raised another USD 86 million, bringing its total funding to more than USD 200 million.

PolyAI positions itself as an Agentic Dialog Platform with three main layers:

• Agent Studio: a browser-based tool that lets you build an assistant by filling in information and clicking options, with no code required.

• Dialog-RSN-1: PolyAI's latest AI model, which hears and understands the caller's voice directly, without first converting speech to text.

• Developer toolkit: for people who code and want to embed the assistant in their own systems or applications.

Core mechanism: A typical voice assistant has to handle three steps in sequence: converting speech to text, working out whether the caller has finished speaking, and only then generating a reply. This process easily causes delays and communication errors. With Dialog-RSN-1, PolyAI handles all three steps at once, making conversations faster and more natural. This technology is especially useful in difficult situations, such as when callers speak haltingly, read out long strings of numbers or call from noisy environments.

2. Ideal users

PolyAI is not an AI chatbot for personal use. It is aimed at businesses with high call volumes that want to automate customer service.

• Businesses with customer service call centers (banking, insurance, utilities, telecoms): Automatically answer repetitive calls such as bill inquiries, outage reports and identity verification, then pass complex cases to staff. Utility company PG&E uses PolyAI to answer power outage calls, while UniCredit bank uses it to handle credit card questions.

• Restaurants, hotels and resorts: Take table and room bookings and answer questions about opening hours and member offers around the clock, even during busy periods.

• Customer service managers: Write and edit the assistant's scripts without waiting on the technical team, while monitoring call quality as it happens.

• Developers and startups building voice products: Plug the Dialog-RSN-1 model directly into their apps, pay per second of use, with no large contract required.

• Marketers and product managers who want to experiment: Use the free trial credit to build a sample assistant as a basis for convincing leadership before a larger investment.

3. PolyAI's standout features

Audio-native Dialog-RSN-1 model: fast and "a good listener"

Dialog-RSN-1 can handle three tasks at once: listening, detecting turns in the conversation and generating a reply. According to PolyAI, the model responds in under 0.3 seconds, scores 89.8 for turn-taking accuracy and misrecognizes only about 3.7% of words. As a result, the assistant rarely interrupts callers and conversations feel more natural. Businesses can also customize how the assistant waits, for example by telling it to wait until the caller has finished reading out an order number before replying.

Agent Studio: build a voice agent without code

Agent Studio divides setup into four areas: Behavior (personality, rules and things the assistant must not do), Knowledge (FAQs, PDF documents, links), Flows (multi-step tasks such as booking, payment and verification) and Voice (voice tuning). This lets customer service staff update answers themselves whenever policies change, without needing a developer.

Test thoroughly before going live

Every change starts in a test area (Sandbox). You can move it to a pre-release area (Staging) to test with a real phone number, then publish it to the live version (Live) for customers. This prevents a small script error from affecting thousands of customers.

Multiple channels, multiple languages and easy integration

The assistant supports 24+ languages and works over phone, web chat, SMS and WhatsApp. PolyAI connects out of the box with popular contact center systems (Genesys, Five9, Amazon Connect, Twilio and more), customer management software and internal knowledge bases. For difficult cases, the assistant can transfer the call to a human agent.

Easy to add to existing apps

For developers, Dialog-RSN-1 uses the same connection method as OpenAI's voice model. So an app already running on OpenAI needs only minor changes to switch over. You can also use PolyAI's built-in voices or pair it with another voice tool such as ElevenLabs.

4. Benefits of using PolyAI

• 24/7 support: Always picks up calls, including at night, on weekends and at peak hours, so fewer customers are missed.

• Lighter workload for staff: Handles frequently asked questions automatically, so staff can focus on more complex cases.

• Natural conversation: Customers can speak in their own words instead of navigating keypad menus.

• Flexible pricing: Billed per second of use, with no minimum fee and free trial credit.

• Fast deployment: A sample assistant can be built in about 10 minutes, while a full rollout for a business usually takes a few weeks.

• Strong security: Meets international security standards such as ISO/IEC 27001 and SOC 2, and complies with data protection rules such as GDPR.

Detailed guide to using PolyAI

Below are the steps to build an AI assistant that answers frequently asked questions using PolyAI's Agent Studio. According to the official guide, you can finish a sample assistant in about 10 minutes. Button names are kept in English so they are easy to find in the interface.

Step 1: Visit the site and create an account

1. Go to the PolyAI homepage and click Get your API key, Start Building or Try Free.

2. Choose Sign up with Google for quick sign-up, or enter your first name, last name, email and password.

3. The password must be at least 12 characters and include at least 3 of these 4 types: lowercase letters, uppercase letters, numbers and special characters. Click Create account, then verify your email.

Step 2: Create an agent and choose the right settings

1. On the Agent Studio home page, click + Agent.

2. Name the agent, choose the response language and voice, and enter your website.

3. Click Next to open the workspace.

Note: If you don't code, follow this guide using Agent Studio. If you are a developer and want to embed the assistant in your own app, get an API key and see PolyAI's technical documentation.

Step 3: Add knowledge and write instructions for the AI assistant

1. In the navigation bar, select Knowledge > FAQs, then click Add topic to create a new topic.

2. Name the topic, add up to 20 sample questions customers might ask, and enter the matching answer.

3. To add information faster, you can upload a PDF file, paste the URL of a policy page or connect a data source in the Connected tab.

4. Go to Behavior to set the agent's personality, tone and operating limits (guardrails). To handle multi-step tasks such as booking appointments, use Flows.

Note: All changes are saved on a branch in the Sandbox environment and do not affect the system currently serving real customers.

Step 4: Test, edit and publish

1. Click the phone icon in the top-right corner, select the Sandbox environment and start talking to the agent.

2. Click the webchat icon and open Settings to show tool calls and cited sources. This lets you check how the agent handles requests and looks up information.

3. If an answer is not accurate, go back to Knowledge or Behavior to update the data and settings, then try again.

4. Phone numbers are only available in the Staging and Live environments. Move your branch to Staging, go to Voice > Numbers, select Add number to add a number and make a test call.

5. Once testing is complete, go to Deployments and click Publish in the top-right corner to put the agent into service in the Live environment.

Tips for optimizing your voice assistant

• Use natural sample questions: Instead of only entering "Opening hours?", add natural phrasings such as "What time do you close?" or "Are you open on Sundays?". Make full use of the 20 sample questions for each important topic so the agent recognizes many ways of saying the same thing.

• Keep answers short: Callers find it hard to remember long information during a phone call. Each reply should focus on 1–2 key points, then the agent can ask: "Would you like me to send the details by SMS?".

• Set conversation rules: With Dialog-RSN-1, you can instruct the agent to wait until the caller has read all 10 characters of an order number before confirming, instead of replying midway. Also set up call transfer to a human agent (human handoff) for complaints or upset customers.

PolyAI pricing

PolyAI does not offer monthly or yearly Free/Pro plans. Instead, it uses two main billing options plus free trial credit (data updated 10 November 2026).

All options include security, SIP integration and cost tracking. Beginners should use the trial credit to build a demo, developers should choose the Platform API, and businesses should contact PolyAI for a quote. In Vietnam, note that PolyAI charges in USD via international cards and that Dialog-RSN-1 currently supports English only; check Vietnamese language support before deploying.

Strengths and weaknesses

Key strengths

• Speed: Responds in under 0.3 seconds, sounding close to a real person.

• Interface: Agent Studio is easy to understand; people with no coding skills can build a sample assistant in about 10 minutes.

• Reliability: Used by many major brands, holds security certifications and allows thorough testing before going live.

• Developer-friendly: Easy to switch over from OpenAI's tools, with per-second billing.

Weaknesses to note

• Vietnamese support not confirmed: The Dialog-RSN-1 model currently supports English only, and the platform has not published the full list of its 24+ languages.

• Limited trial: Allows at most 2 concurrent calls; once the trial balance runs out, users must top up to make new calls.

• Enterprise pricing not public: Businesses will find it hard to budget before talking to PolyAI's sales team.

• Phone lines not included: The pay-as-you-go option does not include phone numbers; users need to rent them separately from another provider.

• Few independent reviews: Self-serve sign-up only launched in October 2026, and most performance figures are currently published by PolyAI itself.

• Requires regular monitoring: The assistant may give wrong answers if the uploaded documents are incomplete or outdated.

Overall review

Automating a call center is not just about letting AI answer in place of people; it is also a way for businesses to streamline customer service and reduce repetitive calls. With fast responses and simple setup tools, PolyAI offers an approach worth trying for businesses that handle large call volumes. That said, Vietnamese language support remains a factor to weigh when deploying in Vietnam.

Rather than only reading about the features, you can start with the free trial, build a voice assistant yourself and see whether PolyAI truly fits your business operations.