What is Amazon Lex V2? - Amazon Lex
Paying for Are You a First-time User of Amazon Lex V2?Using Amazon Lex V2 with an AWS SDK

What is Amazon Lex V2?

Amazon Lex V2 is an AWS service for building conversational interfaces for applications using voice and text. Amazon Lex V2 provides the deep functionality and flexibility of natural language understanding (NLU) and automatic speech recognition (ASR) so you can build highly engaging user experiences with lifelike, conversational interactions, and create new categories of products.

Amazon Lex V2 enables any developer to build conversational bots quickly. With Amazon Lex V2, no deep learning expertise is necessary—to create a bot, you specify the basic conversation flow in the Amazon Lex V2 console. Amazon Lex V2 manages the dialog and dynamically adjusts the responses in the conversation. Using the console, you can build, test, and publish your text or voice chatbot. You can then add the conversational interfaces to bots on mobile devices, web applications, and chat platforms (for example, Facebook Messenger).

Amazon Lex V2 provides integration with AWS Lambda, and you can integrate with many other services on the AWS platform, including Amazon Connect, Amazon Comprehend, and Amazon Kendra. Integration with Lambda provides bots access to pre-built serverless enterprise connectors to link to data in SaaS applications such as Salesforce.

For bots created after August 17, 2022, you can use conditional branching to control the conversation flow with your bot. With conditional branching you can create complex conversations without needing to write Lambda code.

Amazon Lex V2 provides the following benefits:

  • Simplicity – Amazon Lex V2 guides you through using the console to create your own bot in minutes. You supply a few example phrases, and Amazon Lex V2 builds a complete natural language model through which the bot can interact using voice and text to ask questions, get answers, and complete sophisticated tasks.

     

  • Democratized deep learning technologies – Amazon Lex V2 provides ASR and NLU technologies to create a Speech Language Understanding (SLU) system. Through SLU, Amazon Lex V2 takes natural language speech and text input, understands the intent behind the input, and fulfills the user intent by invoking the appropriate business function.

     

    Speech recognition and natural language understanding are some of the most challenging problems to solve in computer science, requiring sophisticated deep learning algorithms to be trained on massive amounts of data and infrastructure. Amazon Lex V2 puts deep learning technologies within reach of all developers. Amazon Lex V2 bots convert incoming speech to text and understand the user intent to generate an intelligent response so you can focus on building your bots with added value for your customers and define entirely new categories of products made possible through conversational interfaces.

     

  • Seamless deployment and scaling – With Amazon Lex V2, you can build, test, and deploy your bots directly from the Amazon Lex V2 console. Amazon Lex V2 enables you to publish your voice or text bots for use on mobile devices, web apps, and chat services (for example, Facebook Messenger). Amazon Lex V2 scales automatically. You don’t need to worry about provisioning hardware and managing infrastructure to power your bot experience.

     

  • Built-in integration with the AWS platform – Amazon Lex V2 operates natively with other AWS services, such as AWS Lambda and Amazon CloudWatch. You can take advantage of the power of the AWS platform for security, monitoring, user authentication, business logic, storage, and mobile app development.

     

  • Cost-effectiveness – With Amazon Lex V2, there are no upfront costs or minimum fees. You are charged only for the text or speech requests that are made. The pay-as-you-go pricing and the low cost per request make the service a cost-effective way to build conversational interfaces. With the Amazon Lex V2 free tier, you can easily try Amazon Lex V2 without any initial investment.

Paying for

Amazon Lex V2 charges you only for the text or speech requests that you make. This model gives you a variable-cost service that can grow with your business while giving you the cost advantages of the AWS infrastructure. For more information, see Pricing.

When you sign up for AWS, your AWS account is automatically signed up for all services in AWS, including . However, you are charged only for the services that you use. If you are a new customer, you can get started with for free. For more information, see AWS free tier.

To see your bill, go to the Billing and Cost Management Dashboard in the AWS Billing and Cost Management console. To learn more about AWS account billing, see the AWS Billing User Guide. If you have questions concerning AWS billing and AWS accounts, contact AWS Support.

Are You a First-time User of Amazon Lex V2?

If you are a first-time user of Amazon Lex V2, we recommend that you read the following sections in order:

  1. Amazon Lex V2 core concepts – This section introduces Amazon Lex V2 and the features that you use to create a chatbot.

  2. Getting started with Amazon Lex V2 – In this section, you set up your account and test Amazon Lex V2.

  3. API Reference – This section contains details about API operations.

Using Amazon Lex V2 with an AWS SDK

Beyond the console interface, Amazon Lex V2 provides comprehensive programmatic access through AWS SDKs. This enables you to integrate conversational AI capabilities directly into your applications, automate bot management tasks, and build scalable solutions.

When you use an AWS SDK with Amazon Lex V2, you can:

  • Automate bot creation and management – Programmatically create, update, and deploy bots without manual console interaction

  • Integrate with existing applications – Add conversational interfaces to web applications, mobile apps, and enterprise systems

  • Scale bot operations – Manage multiple bots, intents, and slot types efficiently through code

  • Implement custom workflows – Build sophisticated conversation flows that integrate with your business logic

The table below shows the AWS SDKs that support Amazon Lex V2 operations. Choose the SDK that matches your development environment and follow the provided links to get started with installation and implementation.

Programming Language AWS SDK Getting Started Resources
Java AWS SDK for Java 2.x

Developer Guide

API Reference
Python AWS SDK for Python (Boto3)

Getting Started

API Reference
JavaScript/Node.js AWS SDK for JavaScript v3

Developer Guide

API Reference
.NET/C# AWS SDK for .NET

Developer Guide

API Reference
Go AWS SDK for Go v2

Developer Guide

API Reference
Ruby AWS SDK for Ruby

Developer Guide

API Reference
PHP AWS SDK for PHP

Developer Guide

API Reference

To get started with any SDK:

  1. Install the SDK for your preferred programming language using the installation instructions in the Developer Guide

  2. Configure your AWS credentials and region settings

  3. Set up the necessary IAM permissions for Amazon Lex V2 operations

  4. Review the API Reference documentation for the specific operations you need

  5. Start with basic operations like creating a bot or listing existing resources

For detailed examples and step-by-step guidance on creating bots programmatically, see the SDK documentation links provided in the table above.