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What is Amazon Lex?

Last Updated : 23 Apr, 2024
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Amazon Lex is a powerful service provided by AWS used for the development of conversational application interfaces. Its ability to understand various natural languages and automatic speech recognition makes it simpler for users to create interesting user interfaces that resemble real-world conversations. On using this service users can easily build their conversational dashboards without the need for deep learning skills. In this article, we going to discuss Amazon Lex starting with what it is. and having a deep understanding of its workflow and use cases.

What Is Amazon Lex?

Amazon Lex is a modern service tool provided by AWS that is used for building conversational and interactive chatbots and virtual assistants. It facilitates the programmers in creating programs that are understandable and reachable to general-speaking languages with the help of advanced natural language processing capabilities. Its versatile adaptability in the field of conversational AI brings out the innovation and improvement changing the face of Human-Computer Interaction (HCI).

Why Amazon Lex?

Amazon Lex offers many advantages that made it as a right choice for business conversational AI Solutions. The are the some of the main advantages and reasons for usage of Amazon Lex:

  • Natural Language Understanding(NLU) And Automatic Speech Recognition(ASR): Amazon lex enhances the usage of Advanced NLU and ASR technologies facilitating seamless interactions with users through both voice and text inputs. This ensures user-friendly experience and customer satisfaction.
  • Integration With AWS Products: Amazon lex provides seamless integration with other AWS services for scaling and customizing deployments as per business needs. This integration facilitates in simplifying the deployment process and reducing the time-to-market for AI powered solutions.
  • Multi-Platform Deployment Support: With support of multi-platform deployment, amazon lex allows the businesses to reach customers across the various channels like websites, mobile apps and messaging platforms. This facilitates in maximizing the engagement potential.
  • Pay-As-You-Go Pricing Model: Amazon Lex works on pay-as-you-go pricing model, ensuring cost-effectiveness and accessibility for business of all sizes. This flexible pricing models helps the organizations in managing their expenses efficiently while scaling their conversational initiatives as needed.

What Is Amazon Lex V2?

Amazon Lex V2 is the next generation of Amazon’s conversational AI service. It comes up with providing enhanced features and capabilities for building interactive voice and text-based applications. Its advances NLU (Natural Language Understanding) and Automatic Speech Recognition (ASR) capabilities facilitating more accurate and new interactions with users. It comes with providing scalability and flexibility features helping businesses to easily integrate conversational AI into their applications across various platforms. Amazon Lex V2 helps developers in creating an effective conversational experiences offering businesses with customer engagement and satisfaction.

How Does Amazon Lex Work?

Amazon Lex works on using advanced NLP and Automatic Speech Recognition (ASR) technologies. It allows developers in defining the conversational flows by creating custom voice and text prompts. It integrates with backend services for building interactive chatbots or virtual assistants. Amazon Lex takes the user input and interprets the user input resulting output as understandable context. It supports various platforms for providing a seamless integration into applications, websites or devices. It improves the understandability continuously making it an efficient and dynamic tool for creating and intelligent conversation interfaces.


How To Create An Amazon Lex ChatBot : A Step-By-Step Guide

Step 1: Navigate Amazon Console

  • Navigate to your AWS Account and login with your AWS credentials


Step 2: Navigate To Amazon Lex

  • After login in, you will be landed on console home, then in the search box search for Amazon Lex as shown in the below figure.
  • Once you find service, click on that service to navigate to their.


Step 3: Create A Chatbot

  • After landing into the Amazon lex page, now click on the create Bot option, to start creating the chatbot.


Step 4: Define The ChatBot

  • Specify the name as “OrderDrinks” and description as “The bot is used for ordering and getting a drink
  • Choose Create A role With Basic Amazon Lex Permissions option in Runtime Role.
  • Choose No to the Children’s online privacy protection Act (COPPA).
  • The following screenshot illustrates how the page looks like and where define those.


Step 5: Choose The Bot Language And Speaker

  • Choose the bot language , here we are choosing the English of US.
  • Choose the bot speaker, here we are choosing Ivy in the option.


  • The following screenshot illustrates the successful creation of chatbot.


Step 6: Specify The Intent Details

  • Here in the Intent Details section we have to provide some text to the bot, to make the bot aware for text to respond.
  • The following screenshot illustrates the defining the intent details.


Step 7: Verify And Save The ChatBot

  • Specify the Intent Name as Order.
  • Provide the message as “Great, Let’s get started!”
  • Verify once and save the chatbot.
  • The following screenshot illustrates clearly the successful creation of bot with name “OrderDrink”


Step 8: Add Slots

  • Add the slots with providing name and slot type as shown in the below screenshot.
  • Provide the prompts as shown in the below screenshot. You can add as many slots and prompts as you want.


Step 9: Provide Confirmation Prompts

  • Provide the confirmation prompt as you want or else take the reference as specified in the screenshot.


Step 10: Verify And Save Configuration

  • Verify the defined configuration once and save the configuration.
  • After once clicking on the save button you can we as shown in the below screenshot it will update the resources.


Step 11: Build The ChatBot

  • After completing the above steps successfully, now build the chatbot by clicking on the build button.


Step 12: Test The ChatBot

  • Now, test the chatbot as shown in the below screenshot right side, with drink and jon…
  • If you getting the messages as responses as defined, then you created the chatbot successfully and its working fine.


Use Cases Of Amazon Lex

The following are the use cases of Amazon Lex:

  • It creates voice assistants and virtual agents.
  • The Amazon Lex offers interactive voice response (IVR) self-service options with virtual contact center agents. Users can schedule an appointment or reset their passwords without speaking to a real person. With application bots, productivity is increased.
  • Users can automate basic user actions in their app using clever chatbots. Connecting to other business apps is made simple using Amazon Lambda, and IAM offers comprehensive access control. The informational responses are automated.
  • The Amazon Lex creates conversational responses to often-asked inquiries. With Amazon Kendra‘s natural language search, enhance the Connect & Lex conversation flows for tech support, HR benefits, or banking. It maximizes the use of transcripts’ available data.
  • Chatbots are developed by Amazon Lex utilizing recent call center transcripts. Shorten the weeks-long process of creating a bot to a few hours.

Create An Amazon Lex Bot ( Console )

Key Features Of Amazon Lex

Amazon Lex is an effective preferred service for building conversational interfaces and much more, the following are the popular features of Amazon lex:

  • Natural Language Understanding (NLU): Amazon Lex is able to understand user input at high level using powerful NLP features and facilitates in creating user-friendly and context-aware interactions.
  • Easy Bot Development: By specifying the conversation flows using user-friendly Lex V2 interface, Amazon lex can facilitates the developers in building an easy conversational bots.
  • Real-time Response Adjustment: Amazon lex automatically alters the replies in real time by improving consistency and effortless interactions. This feature ensure the users continue to find chats intresting and content relvant.
  • Integration With AWS Services: It provides seamless integration with AWS lambda helping users in connecting with a wide range of other AWS services. This facilitates with powerful interactions within the broader AWS ecosystem.

Benefits of Amazon Lex

The following are the popular benefits of Amazon Lex:

  • Advanced Speech Recognition And NLP Comprehension: To build a voice language understanding system, the Amazon Lex provides automatic speech recognition and natural language understanding capabilities. Amazon Lex is powered by the same system that drives Alexa. Amazon Lex is able to comprehend the different ways users could express their purpose based on a few example utterances provided by the developer. The spoken language understanding system accepts natural language voice and text input and analyses it to determine its purpose before invoking the relevant action to achieve the user’s objective.
  • Effortless Content Management: In multi-turn talks, managing context is necessary to classify remarks as the dialogue moves along. Users don’t need to create any additional code to maintain the context because context management is already incorporated into Amazon Lex. Once the fundamental need intents are provided, users can create “contexts” to carry out associated intentions. The creation of conversational exchanges is accelerated, and bot design is simplified.
  • Telephonic Audio Support At 8kHz: In order to increase speech recognition accuracy for telephony applications, the Amazon Lex speech recognition engine was trained on telephone audio (8 kHz sample rate). When building a conversational bot using Amazon Lex, the 8 kHz capabilities allow for enhanced realism with telephone speech interactions, such as through a contact center application or help desk.
  • Failitation Of Multi-Turn Conversations: Once it has been identified, users will be asked for information that is required for the intent to be fulfilled. The development of multi-turn dialogues for chatbots is made simple by Amazon Lex. Customers only need to list the slots and criteria they want their bot users to input, and Amazon Lex will take care of organizing the conversation by prompting them for the appropriate slot.
  • Strong Lifecycle Management: Users can add versioning to their Intents, Slot Types, and Bots using Amazon Lex. Versioning and rollback features make it straightforward to manage code while testing and deploying in a multi-developer scenario. Each Amazon Lex bot can have a variety of aliases and versions assigned to it, including “production,” “development,” and “test“. This enables users to continuously enhance and modify the bot and release new versions under the same alias. There is no requirement to update each client every time the bot releases a new version.
  • One-Click Platform Deployment: They can save time and money on multi-platform development by publishing their bot-to-chat services directly from the Amazon Lex dashboard with the help of Amazon Lex. Sophisticated formatting features offer a natural user experience for chat platforms like Facebook Messenger, Slack, and Twilio SMS.

Get API Token For Amazon Lex

To get an API token for Amazon Lex, you will need to create an AWS Identity and Access Management (IAM) user with appropriate permissions to access your Amazon Lex bot. Here are the general steps for getting an API Token for Amazon Lex:

Step 1: Sign in to the AWS Management Console and navigate to the IAM service page.

Step 2: Create a new IAM user or use an existing one that will be used to access the Amazon Lex API.

Step 3: Attach the “AmazonLexFullAccess” policy to the IAM user. This policy provides full access to Amazon Lex resources, including bots, intents, and slots.

Step 4: Generate an access key and secret key for the IAM user.

Step 5: Use the access key and secret key to authenticate API requests using the AWS SDK or a REST API.

Integration With Other Amazon Services

  • Amazon Connect: You can offer customer care via phone or chat with Amazon Connect, a contact center service that is hosted in the cloud. To build chatbots that can manage client inquiries and refer them to the proper agent, if necessary, you can link Amazon Lex with Amazon Connect.
  • Amazon S3: You may store and access an unlimited amount of data using Amazon S3, which is a highly scalable object storage service. To communicate with data kept in Amazon S3, such as getting customer or order history, use Amazon Lex.
  • Amazon DynamoDB: Data can be stored and retrieved quickly and easily with Amazon DynamoDB, a NoSQL database service. DynamoDB and Amazon Lex can be combined to build chatbots with real-time data access and modification capabilities.
  • Amazon Lambda: You can run code using the serverless computing service Amazon Lambda without setting up or maintaining servers. Lambda functions, which can be used to do operations like sending emails, updating databases, or completing other backend chores, can be triggered by Amazon Lex.
  • Amazon Polly: Text can be transformed into a realistic voice using the text-to-speech tool Amazon Polly. Polly and Amazon Lex can be combined to build chatbots that can converse with users in addition to reacting to their text messages.

Pricing And Scalability of Amazon Lex

Pricing Of Amazon Lex

  • The price of Amazon Lex depends on how many texts or voice requests your bot processes each month, how many slots it fills, and how long each session lasts.
  • You just pay for what you use, with no upfront costs.
  • The cost is listed on the Amazon Lex pricing page and varies by area.

Here the speech requests refer to speech from user input and text requests refer to text from user input.

Input Requests

Cost Per Request

Number Of Requets


7000 speech requests




1000 text requests




Total Amazon Lex Charges for the month


Scalability Of Amazon Lex

  • The extremely scalable architecture of Amazon Lex allows it to process millions of requests daily.
  • It makes advantage of the infrastructure from Amazon Web Services (AWS), which offers high availability and automatic scaling.
  • By changing the configuration parameters or utilizing AWS Auto Scaling, you can quickly increase or decrease the volume of requests handled by your bot.
  • To offer a more scalable and complete solution, Amazon Lex can also be linked with other AWS services like Amazon Connect or Amazon S3.

Limitations And Challenges Of Amazon Lex

Limitations Of Amazon Lex

The following are the limitations of Amazon Lex:

  • Restricted Language Support: English, Spanish, German, French, Italian, and Portuguese are the only languages that Amazon Lex currently supports.
  • Limited Customization: Minimal modification options are available despite the fact that Amazon Lex offers a variety of pre-made intents and slot types.
  • The Complexity Of Integration: Connecting Amazon Lex with other services might be difficult and may need programming knowledge.
  • Absence Of Sentiment Analysis: For some use cases, Amazon Lex’s lack of built-in sentiment analysis may be a drawback.

Challenges Of Amazon Lex

The following are the challenges of Amazon Lex:

  • Natural Language Processing: A thorough grasp of user behavior and natural language processing (NLP) is necessary to create a conversational interface that works well.
  • Conversation Design: Creating a conversational flow that feels natural and intuitive for users can be difficult and may call for a lot of testing and iteration.
  • Data Security And Privacy: Careful consideration of privacy and security measures is necessary while collecting and handling sensitive user data.
  • Training And Upkeep: The chatbot needs constant training and upkeep, which requires continuing resources.


In Conclusion, Amazon lex is an efficient platform for conversational interfaces that helps programmers in easily designing the complex chatbots and virtual assistants. Its integration with natural languages facilitates in better understanding and strong functionalities supporting in businesses to enhance the customer interactions and streamlining processes. Amazon lex is a cutting edge technological advancements for promoting innovation and improving our interactions with automated conversational systems.

Amazon Lex – FAQ’s

What Is Amazon Lex Used For?

It is an aws service for building conversational interfaces on using voice and text often integrated with chatbots or virtual assistants.

What Is Amazon Lex And Amazon Polly?

Both the services comes with different functionalities, Amazon lex used for building conversational interfaces whereas Amazon Polly is used for Text to speech (TTS) conversion generating speech from text.

Is Amazon Lex Available In India?

Yes, Amazon Lex is available in the Asia Pacific (Mumbai) region, making it accessible in India.

Is Amazon Lex Expensive?

Based on the service usage, amazon lex pricing keeps on varying, It has several pricing tiers but also a pay-as -you-go model with free-tier options.

What Is The Difference Between Lex And Policy?

Amazon Lex will focus on building chatbots and conversational interfaces whereas Amazon Polly focuses on converting text to realistic voice.

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