The power of App Inventor: Democratizing possibilities for mobile applications

In June 2007, Apple unveiled the first iPhone. But the company made a strategic decision about iPhone software: its new App Store would be a walled garden. An iPhone user wouldn’t be able to install applications that Apple itself hadn’t vetted, at least not without breaking Apple’s terms of service.

That business decision, however, left educators out in the cold. They had no way to bring mobile software development — about to become part of everyday life — into the classroom. How could a young student code, futz with, and share apps if they couldn’t get it into the App Store?

MIT professor Hal Abelson was on sabbatical at Google at the time, when the company was deciding how to respond to Apple’s gambit to corner the mobile hardware and software market. Abelson recognized the restrictions Apple was placing on young developers; Google recognized the market need for an open-source alternative operating system — what became Android. Both saw the opportunity that became App Inventor.

“Google started the Android project sort of in reaction to the iPhone,” Abelson says. “And I was there, looking at what we did at MIT with education-focused software like Logo and Scratch, and said ‘what a cool thing it would be if kids could make mobile apps also.’”

Google software engineer Mark Friedman volunteered to work with Abelson on what became “Young Android,” soon renamed Google App Inventor. Like Scratch, App Inventor is a block-based language, allowing programmers to visually snap together pre-made “blocks” of code rather than need to learn specialized programming syntax.

Friedman describes it as novel for the time, particularly for mobile development, to make it as easy as possible to build simple mobile apps. “That meant a web-based app,” he says, “where everything was online and no external tools were required, with a simple programming model, drag-and-drop user interface designing, and blocks-based visual programming.” Thus an app someone programmed in a web interface could be installed on an Android device.

App Inventor scratched an itch. Boosted by the explosion in smartphone adoption and the fact App Inventor is free (and eventually open source), soon more than 70,000 teachers were using it with hundreds of thousands of students, with Google providing the backend infrastructure to keep it going.

“I remember answering a question from my manager at Google who asked how many users I thought we'd get in the first year,” Friedman says. “I thought it would be about 15,000 — and I remember thinking that might be too optimistic. I was ultimately off by a factor of 10–20.” Friedman was quick to credit more than their choices about the app. “I think that it's fair to say that while some of that growth was due to the quality of the tool, I don't think you can discount the effect of it being from Google and of the effect of Hal Abelson's reputation and network.”

Some early apps took App Inventor in ambitious, unexpected directions, such as “Discardious,” developed by teenage girls in Nigeria. Discardious helped business owners and individuals dispose of waste in communities where disposal was unreliable or too cumbersome.

But even before apps like Discardious came along, the team knew Google’s support wouldn’t be open-ended. No one wanted to cut teachers off from a tool they were thriving with, so around 2010, Google and Abelson agreed to transfer App Inventor to MIT. The transition meant major staff contributions to recreate App Inventor without Google’s proprietary software but MIT needing to work with Google to continue to provide the network resources to keep App Inventor free for the world.

With such a large user base, however, that left Abelson “worried the whole thing was going to collapse” without Google’s direct participation.

Friedman agrees. “I would have to say that I had my fears. App Inventor has a pretty complicated technical implementation, involving multiple programming languages, libraries and frameworks, and by the end of its time at Google we had a team of about 10 people working on it.”

Yet not only did Google provide significant funding to aid the transfer, but, Friedman says of the transfer’s ultimate success, “Hal would be in charge and he had fairly extensive knowledge of the system and, of course, had great passion for the vision and the product.”

MIT enterprise architect Jeffrey Schiller, who built the Institute’s computer network and became its manager in 1984, was another key part in sustaining App Inventor after its transition, helping introduce technical features fundamental to its accessibility and long-term success. He led the integration of the platform into web browsers, the addition of WiFi support rather than needing to connect phones and computers via USB, and the laying of groundwork for technical support of older phones because, as Schiller says, “many of our users cannot rush out and purchase the latest and most expensive devices.”

These collaborations and contributions over time resulted in App Inventor’s greatest resource: its user base. As it grew, and with support from community managers, volunteer know-how grew with it. Now, more than a decade since its launch, App Inventor recently crossed several major milestones, the most remarkable being the creation of its 100 millionth project and registration of its 20 millionth user. Young developers continue to make incredible applications, boosted now by the advantages of AI. College students created “Brazilian XôDengue” as a way for users to use phone cameras to identify mosquito larvae that may be carrying the dengue virus. High school students recently developed “Calmify,” a journaling app that uses AI for emotion detection. And a mother in Kuwait wanted something to help manage the often-overwhelming experience of new motherhood when returning to work, so she built the chatbot “PAM (Personal Advisor to Mothers)” as a non-judgmental space to talk through the challenges.

App Inventor’s long-term sustainability now rests with the App Inventor Foundation, created in 2022 to grow its resources and further drive its adoption. It is led by executive director Natalie Lao.

In a letter to the App Inventor community, Lao highlighted the foundation’s commitment to equitable access to educational resources, which for App Inventor required a rapid shift toward AI education — but in a way that upholds App Inventor’s core values to be “a free, open-source, easy-to-use platform” for mobile devices. “Our mission is to not only democratize access to technology,” Lao wrote, “but also foster a culture of innovation and digital literacy.”

Within MIT, App Inventor today falls under the umbrella of the MIT RAISE Initiative — Responsible AI for Social Empowerment and Education, run by Dean for Digital Learning Cynthia Breazeal, Professor Eric Klopfer, and Abelson. Together they are able to integrate App Inventor into ever-broader communities, events, and funding streams, leading to opportunities like this summer’s inaugural AI and Education Summit on July 24-26. The summit will include awards for winners of a Global AI Hackathon, whose roughly 180 submissions used App Inventor to create AI tools in two tracks: Climate & Sustainability and Health & Wellness. Tying together another of RAISE’s major projects, participants were encouraged to draw from Day of AI curricula, including its newest courses on data science and climate change.

“Over the past year, there's been an enormous mushrooming in the possibilities for mobile apps through the integration of AI,” says Abelson. “The opportunity for App Inventor and MIT is to democratize those new possibilities for young people — and for everyone — as an enhanced source of power and creativity.”