How to become an Alexa developer: A cheat sheet

Alexa has evolved beyond the Amazon Echo into one of the hottest and most ubiquitous platforms in tech. Learn how developers and businesses can leverage the technology.

The launch of the Amazon Echo and its voice service, Alexa, brought virtual assistants out of our smartphones and into our homes and offices. While the Echo is a solid product, Alexa as a voice platform is where the real value is.

After starting off with 100 things Echo devices could do, the number of available Alexa Skills now tops 100,000. With new devices in the Alexa ecosystem, including a new generation of Echo devices, a Smart Oven, Ring cameras, and the Echo Buds, Echo Frames, and Echo Loop, the places where Alexa lives continues to increase, bringing new opportunities to build skills that leverage those modalities. 

As such, the interest in developing tools for the platform has skyrocketed, with many developers eager to jump into the ecosystem. To help developers and companies better understand how to get started working with Alexa and its related services, we've pulled together the most important details and resources.

SEE: 21 technical Alexa Skills IT pros should know (TechRepublic Premium)

Executive summary (TL;DR)

• What is the Alexa developer platform? Alexa is the smart voice assistant platform  inside the Amazon Echo smart speaker and line of smart home devices. Developers can create Skills for Echo devices using the Alexa Skills Kit, or integrate Alexa into an existing product or device through its API via the Alexa Voice Service.
• Why does the Alexa developer platform matter? Alexa is one of the most popular virtual assistants available today, and it helped catalyze the current market for standalone, voice-powered assistants. It is also increasingly being integrated into a host of popular products.
  
• Who does the the Alexa developer platform affect? This affects developers who want to get started working with a voice interface and writing Alexa Skills, as well as businesses that wish to utilize the power of Alexa through its available API.
• When did this launch? Alexa launched in tandem with the Amazon Echo in late 2014, but updates and fixes are delivered regularly, and Amazon is making a concerted effort to reach out to developers.
• How can developers create Alexa skills and integrations? Developers can write Skills for Alexa using the Alexa Skills Kit (ASK) or Alexa Skill Blueprints, add intelligent voice control to additional connected products with the Alexa Voice Service (AVS), or use the Amazon Lex service to build conversational bots.

SEE: All of TechRepublic's cheat sheets and smart person's guides

What is the Amazon Alexa developer program?

Alexa is a smart assistant that relies on human voice commands to perform tasks. The Amazon Echo was the first device to utilize Alexa, and remains one of the primary ways through which these tasks are performed. Smart speakers like the Echo are often set up through a companion app, but the Alexa Voice Service (AVS) can be integrated into other products, as long as they have a microphone and speaker. 

Following the introduction of the Echo, Alexa has also been integrated into smart speakers by Bose, Harman Kardon, and others, as well as in Amazon's Fire TV and Fire tablet series of products. In total, by September 2019, Alexa was available in over 85,000 devices. Amazon also offers the Amazon Lex service, which allows developers to build conversational bots using the same technology that Alexa is based on.

Terren Peterson, an Alexa Champion and the vice president of platform engineering for retail and direct bank at Capital One, said that many people see Alexa as simply a talking speaker. However, Peterson said that the real value of working with Alexa isn't just the ability to talk back to the speaker, but "the ability to be able to change things with your voice."

SEE: AWS re:Invent 2018: A guide for tech and business pros (free PDF) (TechRepublic)

Users interact with Alexa through voice commands called Skills, which are created by developers to enable a specific experience through the Alexa Skills Kit (ASK). Amazon provides pre-built skill models to make getting started easier. These include Smart Home Skills for home automation, Flash Briefing Skills for information and news, Video Skills, Music Skills, and List Skills. For maximum flexibility, you can create a custom interaction model.

Sarah Sobolewski, who works on the PR team for Alexa, said that it is free to use both the ASK to develop skills and the AVS to integrate Alexa. Sobolewski also said that Alexa will continue to play into Amazon's overall business strategy and its work with developers.

"Much like mobile was a decade ago, we see natural user interfaces like speech as a major shift in computing," Sobolewski said. "We're excited by the customer response so far, but it's still very early and think there's a lot of potential in this space."

Additional resources

Why does the Amazon Alexa developer platform matter?

Alexa has helped to drive interest in the use of voice user interfaces. While other services such as Apple Siri, Google Assistant, and Microsoft Cortana launched before Alexa, it's the Amazon service that has become synonymous with voice assistants.

Peterson said that, for software engineering professionals, the popularity of Alexa raises questions about how professionals should be thinking about user voice as an interface. When our hands are stuck on the keyboard, or consumed with our phone, a voice assistant like Alexa gives users access to information and services through hands-free operation, without them having to give up that dexterity." Voice provides an entirely new way of interacting with technology that we believe will fundamentally change and improve people's lives." 

SEE: Smart Cities and Internet of Things (TechRepublic on Flipboard)

The addition of new modalities for Alexa on personal devices, such as the Echo Buds, Echo Frames, and Echo Loop, gives developers the latitude to create new skills that leverage the unique properties of these gadgets not possible with a speaker tethered to an electrical outlet. As of September 2019, there are over 85,000 Alexa-compatible devices. 

When considering working with the platform, Peterson said that businesses should ask: "What are the things that I can be doing with a voice platform that actually drives value?"

With criticism of Silicon Valley tech giants on the rise, Amazon is moving to counteract criticisms of Alexa's behavior and their logging of voice data collected through Alexa. At an event in Seattle in September 2019, Amazon announced a new wake engine that is 50% more accurate, and introduced a privacy hub, allowing customers to delete voice data on a 3- or 18-month basis, and opt out of human reviews, as well as an "Alexa, why did you do that?" command that offers explanations of what Alexa interpreted.

Additional resources

Who does the Alexa developer platform affect?

Any developers or businesses that want to build out and utilize intelligent, voice-powered services will be affected by advances and changes that are being driven by Amazon Alexa.

Alexa is built using artificial intelligence (AI) technologies, but Sobolewski said that would-be developers don't need a background in natural language understanding or speech recognition to get started. Additionally, there are beginner tutorials available as well, so even very junior software engineers can start working with the platform. Non-developers can build their own simple skills using predetermined frameworks called Alexa Skill Blueprints, which were revealed in April 2018. Amazon also offers Alexa SDKs for Node.js, Java, and Python, as well as an ASK Toolkit for Visual Studio Code, making it easy for developers to build Alexa skills using familiar languages and IDEs.

Alexa is not confined to home and consumer use cases. Alexa for Business provides functionality for professional/productivity use cases, and Alexa for Hospitality provides the Alexa experience in hotels for controlling in-room devices, playing music, and contacting the hotel for guest services, among other features. 

Amazon has also introduced the Echo Dot Kids Edition, and provides guidance for developers to build Alexa Skills for children. In September 2019, Amazon introduced the Education Skill API, enabling integrations with Learning Management Systems (LMS), Student Information Systems (SIS), Classroom Management providers, and massively open online courses (MOOCs).

Brian Donohue, another Alexa Champion and a product engineer at Pinterest, noted that businesses building skills should keep in mind that the platform is new and sometimes skill discoverability can present some challenges. "Skills are not sold like a mobile app is," Donohue said. "They are free, and Amazon has said it has no intentions of directly monetizing the platform any time soon."

While skills themselves cannot be sold, there are ways to monetize them. Amazon unveiled in-skill purchasing (ISP) for Alexa Skills in May 2018, which allows developers to sell a one-time purchase for feature or content upgrades, or offer premium content subscriptions. If the Alexa Skill drives customer engagement, developers can earn money through Alexa Developer Rewards. Goods and services can be sold through Alexa Skills.

Startups that want to build new products and services with AVS or ASK have the opportunity to apply to the Alexa Fund, a $100 million fund for investing in new voice technologies. In addition, Amazon offers the Alexa Developer Rewards program, Alexa developer promotions, and AWS promotional credits to discount the cost of AWS resources used for Alexa Skills, or otherwise incentivize developers to build in the Alexa ecosystem.

Additional resources

When did Amazon Alexa launch?

Amazon originally debuted Alexa alongside the original Echo smart speaker in 2014. While the first Echo device was impressive in its own right, the ecosystem around Alexa has grown tremendously over the past few years.

Amazon and its partners have rapidly multiplied the number of Skills for Alexa from a handful when the Echo launched to over 85,000 available today—with more being added almost daily. Amazon has continued to advance the product with new services like its Alexa-powered Music, updates to the Alexa app, and new form factors like the low-cost Echo Dot, the Echo Tap, the Echo Look, and the Echo View, which have helped drive additional interest in the product. Amazon recently added new developer tools like the Alexa Presentation Language (APL) for the Echo Show series, and the Alexa Smart Screen and TV Device SDK, which allows developers to bring the APL to more screen-based smart devices.

Outside of Amazon's proprietary hardware, Alexa is showing up in new and interesting integrations for major brands around the world. Alexa can now be found in notebook PCs, headphones, wearable and smart home devices, as well as in vehicles from Audi, BMW, Ford, Lincoln, Lexus, SEAT, and Toyota. Additionally, some hobbyists are even creating their own versions of the Echo using a Raspberry Pi.

Additional resources

How can developers create Alexa skills and integrations?

Getting started with Alexa as a developer requires an understanding of what pre-formed Skill type is best suited for the use case of your app, or if a custom interaction model is needed to achieve the outcomes desired for your use case. Building with the pre-formed Skill types and associated APIs is easier when getting started with Alexa.

"These APIs give less control over the user's experience, but simplify development since Amazon has already done the legwork to create the voice user interface," Sobolewski, said.

Donohue explained that the Flash Briefing skills "use either an RSS or JSON feed containing the daily items that would be part of the flash briefing." However, using the Smart Home skills API "requires an AWS Lambda function that acts as an adapter for the integration, and an account-linking integration that allows the end user to link their Amazon Alexa account with the smart home appliance account for authenticated control of smart home devices," Donohue said. One example of a Smart Home skill would be using Alexa to control a Philips Hue lightbulb.

For use cases not suited to the aforementioned Smart Home or Flash Briefing Skills or Video, Music, or List Skills, developers can use a custom interaction model. "This is the most flexible kind of skill, but also the most complex, since the developer will need to provide the interaction model," Sobolewski said. "The interaction model is essentially the 'conversation' between Alexa and the user. It maps the various ways users make their request, how Alexa collects more information from the user, how the user can respond, and how Alexa completes the user's request."

Custom Interfaces provide tools for developers to build smart toys that interact with Alexa. Additional APIs are provided for smart home devices that connect to Alexa-powered devices, but do not independently provide Alexa capabilities. Likewise, the Connect Kit aids hardware developers in integrating with Alexa. 

SEE: Amazon's Alexa Skills can borrow each other's tricks now (CNET)

Custom interaction models can use either AWS Lambda or a custom HTTPS-enabled web server for the integration, Donohue said. Although, a "complicated certificate verification that's enforced by Amazon makes developing with Amazon Lambda generally easier," Donohue added. Custom interaction models also support custom slot type syntax, allowing developers to go beyond Amazon's built in types. One Skill utilizing a custom interaction model was developed to tell users the status of the BART transit system in the Bay Area, offering information like when a train is leaving Balboa Park or North Berkeley, for example.

Developers who opt to use Lambda can author the functions in Node.js, Java, or Python, Sobolewski said, while a web service can be built in any appropriate language.

Even if you don't plan on utilizing Lambda, it would be worthwhile to know as you begin to experiment in the ecosystem. Additionally, Peterson recommends that would-be Alexa developers learn Speech Synthesis Markup Language (SSML). There is documentation for it provided by Amazon, and it is worth diving into, Peterson said.

"If I were to do it all over again, I would have probably not skipped by the [SSML] chapter, if you will," Peterson said. "Amazon provides that documentation, I think that I just glossed over it."

Another thing to keep in mind with custom skills is that there are specific formats for the response that your service returns. For example, a JSON response is limited to 8000 characters in its output speech and 24kB.

SEE: Amazon Alexa, why aren't more people doing voice commerce? (ZDNet)

As with any application, understanding how it will be used and what features will be critical is important to do before starting the building process. Unfortunately, Peterson said, analytics for the platform are weak, so potential builders won't be able to glean that many insights. It is very important to learn some of the tenets of voice interface design.

"The ideal scenario is to avoid what some at Alexa have called 'unhappy paths.' Remember that you don't have an 'X' in the upper right corner to click, so if someone goes down a path of no return, they'll get frustrated and never use your skill again," said Joel Evans, an Alexa Champion and the co-founder of Mobiquity.

To get started at the basic level, Amazon provides a tutorial for building a trivial skill in less than one hour. Amazon offers Skills templates and training tutorials in the Alexa Developer Portal. Additionally, developers can tune into live webinar office hours to get answers to technical questions and learn best practices, and pursue more advanced training and certification through Big Nerd Ranch.

Additional resources

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This article was written by Conner Forrest and first published on Feb. 2, 2017. The cheat sheet was updated and republished on Sep. 27, 2019 by James Sanders.