This free online tool makes it so easy to learn how to code, kids are using it to build websites, games, and even apps to help with their math homework

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Many of Repl.it's users are kids teaching themselves how to code.

• An online coding platform called Repl.it is picking up popularity among kids and teenagers, who are using the platform to learn to code and to build apps online.
• Kids enjoy using Repl.it because they can write code without having to install anything on their devices, and they can work with friends on building games and projects -- whether those teammates are their classmates, or someone from the other side of the world.
• They're even using Repl.it to teach each other how to code - the service allows users to collaborate on code, build their own tutorials, and host coding challenges.

Nathan Raikman, a 14-year-old high school freshman from Massachusetts, started coding because he had always been interested in computers. He would watch tutorials online and play around with code by creating new projects. When he found out about coding clubs at school, he became more deeply invested in growing his skills.

However, when he wanted to build more complicated projects, it required him to do some setup - getting started with coding usually requires installing a bunch of other programs, like code editors and software packages, to get started. So about four years ago, Raikman searched for an easier way... and found Repl.it.

Repl.it is an online coding platform that's sort of like a Google Docs for coding, with some elements of a Facebook-style social network. There's a growing community of both amateur and professional developers using the platform. Because of its simplicity, though, it's attracting kids like Raikman.

"When I go to school, I can just go on one computer," Raikman told Business Insider. "I can automatically start coding. It doesn't require any setup. If I want someone to see my stuff I can just send the link to them. I can just send them a URL and they can run the code."

Repl.it founder Amjad Masad calls Repl.it a cross between GitHub and Codecademy. Like GitHub, Microsoft's ubiquitous code-sharing site, users can host software projects that anybody can work on. But like Codecademy, the popular learn-to-code service, users can also find tutorials to help them ramp up.

There are other services like Repl.it: CodePen, PythonAnywhere, and even Amazon Web Services' Cloud9. But they either focus on specific languages and uses (as with PythonAnywhere and the Python programming language), or they're too powerful for beginners.

Repl.it, on the other hand, has found some success because it supports 40 languages, and it supports both novice and experienced programmers. The site currently has over 1 million monthly active users.

How Repl.it started

Growing up in Jordan, Masad didn't own a laptop. When he studied computer science in school, he had to practice coding in a shared lab. This often involved the cumbersome, time-consuming process of installing a slew of software every time he got started on a new machine.

Masad also spent time working at Codecademy. Inspired by these experiences, he wanted to build a platform that allows people to learn to code without leaving the browser, lowering the bar to entry - you don't need a powerful computer to get started; you just need something that access the internet.

Although Repl.it has many professional developers and educators on its platform, Masad says that the service has also seen a rapid growth among kids and teenagers building calculators, games,personal websites, and chatbots. A 13-year-old even built an artificial intelligence program that can recognize written numbers, Masad boasts.

"What captured our attention was when kids started using Repl.it out of their own ambition," Masad told Business Insider. "A lot of kids find out from their friends and teachers or by Googling it. They join this community of a bunch of teenage hackers who are building amazing software together."

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To that point, Repl.it is a social platform, where users can code collaboratively. Repl.it's so-called Multiplayer mode allows people to collaborate on code at the same time, similarly to how Google Docs allows multiple people to edit a document at once.

"A lot of kids are going in the YouTube era and the Snapchat era, and they're used to building things socially," Masad said. They want to show each other their code."

Connecting kids around the world

Raikman normally builds tools that helps him in school, like a program that helps him with the quadratic equation. He's also made timers, calculators, and text-based games. He's run code jams on Repl.it, where he creates coding challenges that other users can participate in. He even got his friends at coding club to use it, too.

Repl.it has also brought together users from outside the United States. Lucy Durrand, a 14-year-old from Scotland, has been learning to code in Python and HTML in her computing class. The class is learning how to use Repl.it to build websites, going so far as to build integrations with Twitter.

"[Repl.it] is really easy to use, and it keeps all your coding files organised rather than having them in odd places saved on your computer and being hard to find," Durrand told Business Insider.

15-year-old Samarth Jajoo from India first started using Repl.it two years ago because he was drawn to its weekly coding challenges. Now, he builds tutorials on Repl.it, such as one about how to make a bot on WhatsApp.

Likewise, 15-year-old Kaldis Berzins from Latvia discovered Repl.it two to three years ago online. He got started in learning to code from online resources like Codecademy, but when he wanted to code, he would have to use apps like Notepad or Sublime. So when Repl.it rolled out support for more languages, Berzins stuck to it.

Now, he's building a shooting game that involves snatching guns, crates and other objects falling from the sky.

"It has a wide variety of languages now which is nice and one of the greatest things was the awesome community behind that," Berzins told Business Insider. "It's nice to be with those people and learn."

With Repl.it, users are holding study sessions together, teaching each other to code and working together to build games and apps. The fact that many of these users are young people makes Masad optimistic about the future.

"All these young people are creating amazing software and collaborating doing it," Masad said. "It's pretty easy to see Repl.it and think it's a learning tool, and it's much more than that. It's a place where people are building things."