Amazon Lex Cheat Sheet

• A service that can help you build conversational interfaces using voice and text.
• Uses automatic speech recognition (ASR) to convert speech to text.
• Uses natural language understanding (NLU) for recognizing the intent of the text.
• Provides highly-engaging user experiences and lifelike conversational interactions.
• Gets more intelligent over time by using deep learning.

Common Use Cases

• AI Chatbots
• Informational bots
• Enterprise Productivity bots
• Voice Assistants

Concepts

• Bots
  • Performs automated tasks such as ordering food or booking flights.
  • Supports multiple intents – for example, a bot can book a reservation or may choose to cancel it.

• Intent
  • A set of actions given to a bot by a user.
  • Intent name
    • A description for the intent (e.g. ‘BookFlights’, ‘OrderFood’)
  • Sample utterances
    • Describes the tone of the intent.
  • How to fulfill the intent
    • Describes the method of fulfilling an intent.
    • Deeply integrates with AWS Lambda to fulfill the intent.
• Slot
  • An optional parameter is used as a part of the intent configuration.
  • Slot type
    • You can create a custom or built-in slot type.
    • Each slot type should have a unique name within an AWS account.

Features

• Lex V2: Next-gen version with improved NLU, multi-language support, and easier bot management.
• Generative AI Integration: Connects with Amazon Bedrock for richer, more human-like responses, QnA, and auto-generated utterances.
• Multi-Region Deployment: Deploy bots across multiple regions for resilience and disaster recovery.
• Conditional Branching: Supports conversation flows that change based on slot values or conditions.
• Composite & Grammar Slots: Combine multiple slots or define structured inputs using custom grammar (SRGS).
• Visual Conversation Builder & Test Workbench: Drag-and-drop design and automated testing of conversation flows.
• Analytics & CloudWatch Integration: Built-in metrics for intent recognition, conversation paths, and drop-off points.
• Enhanced Slot & Intent Support: Expanded built-in slot types and more expressive confirmations (e.g., “Don’t know” / “Maybe”).

Amazon Lex Pricing

• Pay-as-you-go: $0.004 per voice request, $0.00075 per text request.
• Free tier: 10,000 text and 5,000 speech requests/month (first year).

Note: If you are studying for the AWS Certified Machine Learning Specialty exam, we highly recommend that you take our AWS Certified Machine Learning – Specialty Practice Exams and read our Machine Learning Specialty exam study guide.

Amazon Lex Cheat Sheet References:

https://aws.amazon.com/lex/faqs/
https://docs.aws.amazon.com/lex/latest/dg/how-it-works.html
https://aws.amazon.com/lex/pricing/