What is Amazon Lex? - Amazon Lex

What is Amazon Lex?

Amazon Lex is an AWS service for building conversational interfaces for applications using voice and text. Amazon Lex 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 enables any developer to build conversational bots quickly. With Amazon Lex, no deep learning expertise is necessary—to create a bot, you specify the basic conversation flow in the Amazon Lex console. Amazon Lex 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 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.

Amazon Lex provides the following benefits:

  • Simplicity – Amazon Lex guides you through using the console to create your own bot in minutes. You supply a few example phrases, and Amazon Lex 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 provides ASR and NLU technologies to create a Speech Language Understanding (SLU) system. Through SLU, Amazon Lex 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 puts deep learning technologies within reach of all developers. Amazon Lex 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, you can build, test, and deploy your bots directly from the Amazon Lex console. Amazon Lex 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 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 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, 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 free tier, you can easily try Amazon Lex without any initial investment.

Are You a First-time User of Amazon Lex?

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

  1. How it works – This section introduces Amazon Lex and the features that you use to create a chatbot.

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

  3. API reference – This section provides additional examples that you can use to explore Amazon Lex.