One of the most popular apps used by teenagers is becoming a platform for bullying.

Toward the middle of June, a new app called Sarahah popped up on the iTunes store. Within days it had carved itself a place inside the top 200 free apps. Within a month it was number one.

Today, the Saudi-built success story has so far topped the iTunes charts in 30 countries, and is having similar success on Google’s Play Store with in excess of five million downloads.

But Sarahah’s phenomenal popularity isn’t the only thing that’s got people talking, it’s the way it’s being used by bullies.

What is Sarahah?

Sarahah (an Arabic word that roughly translates to ‘frankness’ or ‘honesty’) is an anonymous messaging service created by Saudi Arabian developer Zain al-Abidin Tawfiq.

Initially designed as a platform for providing private, constructive criticism in the workplace, the 29-year-old modified it for social use in 2016 and ultimately launched an app-based English-language version in the middle of this year.

It now positions itself as a service that “helps people self-develop by receiving constructive anonymous feedback”, and according to Tawfiq more than 300 million messages have been sent so far.

How does it work?

Sarahah works by giving each of its users an account and a custom URL that links to it. Whoever has that link then has the ability to leave anonymous message for the user.

This anonymity means that, unlike other social messaging services, communication is entirely one-way – the recipient has no means of responding.

While users were initially sharing their Sarahah URL among their friends and colleagues, it wasn’t long before people began casting their net wide, soliciting feedback from followers and strangers via social media channels like Facebook and Instagram.

But the popularity of Sarahah really took off with a major update issued by image- and video-sharing phenomenon, Snapchat. The July 5 update allowed users to post URLs within their Snaps for the first time, and plenty of Sarahah users began using it to direct others to their account.

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What do teens use it for?

As a Sydney-based 17-year-old told Mamamia, “The messages are usually more likely to be statements about the person, and most of the time it’s criticism. It’s really just an excuse to cyberbully.”

With no way to be identified, no way to respond, it’s a troll’s paradise.

The reviews of the app reflect this.

“I have seen some of the appalling comments teenagers at high school have written to their classmates via this app, hiding behind anonymity,” wrote one iTunes user. “I understand constructive criticism, but who checks on those telling others no one likes them, that they losers and should kill themselves?”

“My son signed up for an account and within 24 hrs someone posted a horrible racist comment on his page including saying that he should be lynched,” another posted. “The site is a breeding ground for hate.”

What does the app's creator have to say about this?

Speaking to Mashable recently, Tawfiq said he is taking steps to ensure his app remains a productive, positive place by filtering certain offensive words and allowing users to block people, for example.

"I really try my best to create an environment that's positive."

What are anti-bullying groups saying?

Speaking to Mamamia, cyber safety expert Jeremy Blackman, of the Alannah and Madeline Foundation, noted that Sarahah is the latest in a long line of anonymous platforms that tend to "encourage unkind, and sometimes very offensive, behaviours" - among them ‘Yik Yak’, secret.ly and ask.fm.

"Unfortunately, start-ups like this don’t prioritise user safety, and Sarahah currently has no function to report cyberbullying or abuse," he said.

"The Apple store recommends users are 17 and over, and this is for good reason – younger teenagers and children will find it very difficult to deal with such abusive anonymous comments, anonymity always makes the scale of abuse worse."

To those being targeted by online abuse or cyber bullying, Blackman advises:

• Block/report the user
• Close your account, if necessary
• Tell a trusted adult (teacher/parent)
• If the situation becomes worse, you can report through the Office of the eSafety Commissioner.

If you are a teen being bullied, 24-hour help is available via Kids Helpline on 1800 55 1800. Adults can call Lifeline on 13 11 14.

Advice for teachers, parents and kids about how to deal with bullying is available via the Alannah and Madeline Foundation's National Centre Against Bullying website.