Instead of a list of friends or contacts that you have to manually add or import from other services, the app lets you “Ruffle” any of your phone’s existing contacts, regardless of whether that person has installed the app or not. While a little confusing at first, after Ruffling a few contacts, we soon realised that Ruffle is sending an SMS notification, sent from Ruffle — not the sender’s SMS plan — to recipients who don’t have the app installed, letting them know that they have a Ruffle waiting for them.

While sending SMS notifications may seem spammy, Ruffle’s co-founders Nick Drewe and Matt Way, both Australians, assured us that the app will only ever send one SMS to any particular phone number. Users who don’t want to be bothered simply need to ignore the message, and they will never receive another notification.

We were a little skeptical about how many people would install the app from the SMS notification, but after Ruffling a handful of people, we started receiving some replies. We just weren’t quite sure who they were from. This is where Ruffle starts to get interesting, and a lot of fun. There’s an excitement to receiving an unexpected Ruffle that is strangely addictive.

Ruffle’s stand-out feature is the ingenious “de-pixelation” effect that is uses to reveal images. When you first view a Ruffle, the image is completely pixelated, just a few squares of color that make it next to impossible to determine what the image actually is. To reveal the full-resolution image, you have to slowly swipe your finger across the screen which gradually de-pixelates the image. This cleverly serves two purposes. First, if you de-pixelate the image half-way and realise that you’re starting to see the outline of something you would rather not see, you can simply list your finger from the screen and the image re-pixelates.

But Ruffle’s de-pixelator also creates a suspense and anticipation to receiving and viewing a Ruffle that we haven’t seen before. While testing, it wasn’t uncommon to see someone announce that they had received a Ruffle, and have a few people crowd around to watch the slow de-pixelation.

Unlike Snapchat, pictures received on Ruffle stick around on your phone until you delete them, and the ability to forward a Ruffle means that you should never send anything on Ruffle that you wouldn’t want to end up being made public. We found Ruffle was more fun for sending GIFs, memes, and reaction images than nudes anyway.

As for other safety concerns, Drewe and Way said this was their top priority when developing the app. Ruffle has a zero tolerance policy for inappropriate content, and users simply need to swipe left on a Ruffle from the inbox to permanently block the sender.