Amazon Lex Specializedsince 2016
A service for building conversational interfaces using voice and text
What It Does
Amazon Lex is a service for building conversational interfaces for chatbots and voice bots. Using the same natural language understanding (NLU) and automatic speech recognition (ASR) technology as Alexa, it understands user intent and returns appropriate responses.
Use Cases
Used for customer support chatbots, call center interactive voice response (IVR), internal help desk bots, and conversational interfaces for reservation systems.
Everyday Analogy
Think of it like a restaurant receptionist. They understand the customer's (user's) requests like 'I'd like to make a reservation' or 'I'd like to see the menu' (intent), gather the necessary information (date, party size), and take the appropriate action (process the reservation).
What Is Lex?
Amazon Lex is a service for building conversational AI. You define intents (user goals), slots (required information), and fulfillment (processing) for a bot, and it collects information through dialogue with users and executes processing via Lambda functions. It supports both text and voice.
Intents and Slots
An intent is the goal a user wants to achieve (e.g., 'Book a hotel'). Slots are the information needed to fulfill the intent (check-in date, number of nights, room type). Lex collects slot values through conversation with the user, and once all slots are filled, it executes the fulfillment (Lambda function).
Getting Started
Create a bot in the Lex console and define intents and slots. Test the conversation in the test window to verify behavior. Integrate with Amazon Connect for a call center voice bot, or embed it in a website for a chatbot.
Things to Watch Out For
- Pricing differs between text requests and voice requests. Voice requests have a higher unit price
- The legacy 12-month free tier (accounts created before July 15, 2025 only) included 10,000 text requests and 5,000 voice requests per month; newer accounts use the credit-based free plan (up to $200 in credits) (as of August 2026)
References (Official AWS Resources)
The primary sources for this page are the official AWS website and documentation. Check the official pages below for the latest specifications and pricing.
If this page and the official documentation disagree, treat the official documentation as authoritative.
