Amazon Lex
Amazon Lex is a service from Amazon Web Services for building conversational interfaces — chatbots and voice bots — using the same automatic speech recognition and natural language understanding technology behind Alexa.
AI Practitioner focus
- Lex V2 builds multi-turn voice/text bots using automatic speech recognition and natural-language understanding around intents, utterances, slots, sessions, and fulfillment.
- Choose Lex for a structured conversational interface; choose a foundation-model assistant when broad generative reasoning is required, and still constrain external actions through deterministic authorization.
Key points
- Handles both text and voice conversations, converting speech to text and then determining the user’s intent from it.
- Built around intents (what the user wants), utterances (the phrasings that signal an intent) and slots (the parameters a fulfilment step needs).
- Fulfils intents by invoking AWS Lambda functions, which is how a bot actually looks something up or completes a transaction.
- Commonly paired with Amazon Connect to automate the front line of a contact centre before escalating to a human agent.
- Requires no machine learning expertise — a pre-trained service rather than a model you build in Amazon Sage Maker.
- The boundary that matters: Lex builds the conversation. Amazon Polly only speaks text aloud, Amazon Transcribe only converts speech to text, and Amazon Kendra answers search queries over a document corpus rather than holding a dialogue.