We first looked at Onavo in May 2011, but since then the service has rolled out to Android as well, and most of the initial bugs have been fixed. Battery life is also not affected anymore, so we can now wholeheartedly recommend Onavo. This post is updated to reflect new changes in the App.

Many of you probably know and use Opera Mini, which allows the user to browse quickly, but also saves money by compressing data before it arrives on your phone. The result is that some images might look slightly more pixelated, but at the end of the day it is well worth the cost savings and improved speed.

Now what if you can have these kind of savings on almost all the apps you use on your iPhone, iPad or Android device? Charl Norman pointed me in the direction of Onavo (available on iPhone, iPad and Android) – somewhat strangely named, and yes I was skeptical. But anyway, I installed the free app to try it out. Onavo acts as a proxy server that first compresses all data before it arrives on your phone.They are currently focussing the app on world travellers who have to face giant data costs, but nothing prevents you from using it all the time. Take a look at the video below for a better idea…

The part that intrigued me was how Onavo would do such a thing on even a traditionally very locked down device like the iPhone. Well -its pretty straightforward it seems. Onavo installs an XML configuration profile on your device, similiar to what you might use in enterprise setups (if you ever used iPhone Configuration Utility, you will know it). The phone first asks you your passcode if necessary, and explains to you how the profile works. Inside the Onavo app a reporting dashboard exists to let you know how much compression is going on with the data before it reaches your phone. So how well does it work?

In a word – Great. I did not have a single issue with one of my apps. You can see the effect of Onavo everywhere you go on the iPhone. Regardless of the app, if the image is small, it is slightly pixelated. Facebook, News24, Twitter, Maps, Safari – everywhere you can see it being used. You can go look at the dashboard to see the savings, with apps like News24 and Twitter which utilizes small images being biggest beneficiaries of the compression.

Web browsing works well, with all sites rendering correctly. Images above a certain size is not compressed it seems, which makes sense. If you want to see a photo full screen in Facebook, you do not want to see pixelation, right? There might still be some compression going on, but pixelation is gone on those images. See below for an example of the image compression. While the effect is not very pretty, users of Opera Mini should be used to it by now, and I am fine with while I am using 3G. Another benefit is that very slow Edge based networks work a little better through Onavo, so if you are in an area with poor reception, Onavo might make your web browsing a little zippier.

Onavo is quite well thought out – it only functions on 3G data, and switches off the moment you go onto wifi. So once you are within your wifi network, images again appear crisp, without any interaction required from you. Streaming services seem to be the only thing that does not work with Onavo at the moment. By “does not work” I mean it does not compress this data, but it still works fine. Onavo even compresses Exchange data, but you luckily have the option to switch this off. Im pretty sure if you are using a Exchange account on your device, your workplace might not appreciate their data running through some proxy server somewhere in the US. I switched it off, but maybe you are fine with it.

OK, so it works well, and I did not find any issues in any apps using it. But there is one problem, and it is the same problem people face when using Opera Mini. These services run as a proxy server between your device and the actual website or app service. This means that all data is sent through them, which can raise some alarm bells for the security conscious between us. And face it – in times like the these where attacks happen to even some of the biggest online businesses, can we really trust this type of solution? If you have used Opera Mini (apparently these users are everywhere, even in the smartphone era), you clearly have no qualms about this. But it might be something you want to take note of. I have to point out though – many sites that use SSL will keep on being encrypted, and Onavo does not touch this data. You of course the issue to instantly switch off Onavo by just clicking “Stop Savings” in the app if you feel you might be doing something confidential.

So how much did Onavo decrease my data usage? I only used it a few days now, and the overall savings has been around 50%, but you can also go and drill down to see which apps get the most compression. News24 is one of the apps I use a lot, and it got a 61% data saving (clearly they can optimise their images somewhat). While its not quite the savings that Onavo claim, I think its good enough. As an added bonus I noticed that many US only apps on the iPhone just worked, because the Onavo proxy server is sitting in the US, similiar to some VPN solutions. But I am pretty sure this will fall away once services like Pandora catches on to this.

So is Onavo a must have app? It depends on your usage – if you do a lot of very secure browsing on your device, and you do not want to trust some proxy server, then of course no. But then again, not all users of iPhone and Android are power users. We all know the type – many people just use it as a phone, and occasionally browse some news sites, and do quick searches on the Wikipedia.  For these lighter users of the iPhone and Android, and those who are particularly sensitive about their anaemic data plans, it might make perfect sense to use Onavo…