Nexmo Amazon Lex Connector in Public Beta

Published May 11, 2017 by Sam Machin

At Nexmo, we are really excited by the prospects of Bots and AI. We believe that natural language communications are the next revolution in how we interact with technology. As a communications platform, we are well placed to take part in this revolution and we want you to be too.

Amazon recently released their Lex Engine. Lex is “what’s inside Alexa”. It is the core parts of the Alexa service that powers devices such as the Echo, but in a more modular component which you can use to build into your own systems.

Announcing the Nexmo Lex Connector

Today, we are pleased to announce that the Nexmo Lex Connector is in public beta, allowing any Lex bot to now be accessed via a Nexmo powered phone call with just a few lines of configuration. This opens up all sorts of exciting possibilities for using bots. For example, in customer service roles; imagine a train company that wants to have an easy way for their customers to ask simple questions like “When is the next train from Kings Cross to Hogsmeade”. Instead of having these questions answered by a customer service operator they can now build a bot to return simple timetable results and offer that bot on a phone number that they advertise to their customers. This results in quicker responses and reduces the cost and workload required for simple questions.

The Nexmo Lex Connector is the result of a collaboration between Nexmo Developer Relations, Vonage Garage and Product teams. It’s also the first connector built on our exciting new Voice API WebSocket feature.

How Does it Work?

When an inbound call is placed to a Nexmo number, you simply instruct Nexmo to connect the call via WebSocket to the Lex Connector. The connector breaks the audio up into sections and passes those to Lex using credentials and parameters you supply. Audio responses from Lex are played back through the WebSocket to the Nexmo platform and on to the caller.

Nexmo Amazon Lex Connector Flow Diagram

The above diagram shows the most common use case: the inbound call coming from a phone. But it is also possible for the inbound leg to be a WebSocket. So, you could have bots powered by Amazon Lex, IBM Watson, Microsoft Bot Framework and, and a number of humans via their phones all in the same conference call. We’ll let you think on that some more!

How to Get Started

You can use the Nexmo Lex Connector in two ways.

We are providing a hosted version that you can use to connect your calls from our Voice API to Lex. You can read how to getting started with the hosted version in the Nexmo Lex Connector docs.

We have also open sourced the code behind the connector. You can find the code and instructions on how to use it on GitHub.

How to Provide Feedback and Get Help

We’re always looking for feedback on ways we can improve our products or further innovate with them. The Nexmo Lex Connector is in public beta so we would love your feedback. We’ll use your feedback to inform decisions around additional features, other bot connectors, pricing (the outbound WebSocket to the Lex Connector is free during beta) and more. You can provide feedback and request support by joining the Nexmo Slack Community and sharing your thoughts in the #lex-connector channel, raising an issue in the Nexmo Lex Connector GitHub repo, or by sending an email to

We’re excited to see how this enables you to innovate with voice.

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