OpenSignal is hiring - Startup Interview

29 Oct 2012

James Robinson is cofounder and CTO of OpenSignal you can reach him on [email protected] or @jamescrr.

Hi James! What is OpenSignal?

James: We're the world's biggest project to map cell and wifi signal.
Our database of crowdsourced cellular and wifi readings powers a recommendation engine that helps people choose the best cellular network for them. We also use this data to provide intelligence to the networks themselves to help them improve their service. The global market for this sort of data is huge - around a billion dollars a year is spent by the networks collecting this, and there are many more applications for the data.

How did you come up with the idea of OpenSignal?

James: We knew that getting good signal was a problem - especially outside of Europe - as my co-founders had set up an e-commerce business ( selling amplifiers for cell phone signal. We also knew that the coverage maps networks provide are over optimistic and hard to compare. When we came across the APIs in Android that allow you to read the signal strength we realised we could build something that would solve this. Now the app has 2.5 million downloads and we've collected readings from 15% of the world's wifi routers, but it's really just the beginning: 85% are left to find!

OpenSignal collects millions of data points, can you talk about technology behind it?

James: In fact we collect about 15 million datapoints a day currently! Datapoints start their life as readings taken on Android phones and tablets all over the world. After living on the phone in SQLite for a while they're sent to a MySQL database where we store them temporarily and we run a bunch of mysql jobs and some PHP every hour to proccess the data.

We archive the raw data and typically query it using Hadoop when companies request custom analysis, but every one of those 15m points will make its mark by contributing to our the tables we use to run our Network Rank algorithm - the thing that says for each area on a map whose service is the best. Data gets visualised as heatmpas using tiles custom made with PHP and store on S3, we serve these up over a google map on our website.

We also run one-off reports on our data, this one just got referenced by the BBC and lots of new sites worldwide - Politics of wifi names. Some of the tools we might use in making reports or doing analysis include: Google Viz, R, Fusionh Tables, PostGres, QGis.We use librariers/frameworks wherever we can, but we love to make custom stuff too.

How is it working at OpenSignal? Who is in the team?

Currently there are just three of us co-founders - me, Brendan Gill and Sam Westwood - working full time, we're backed by some great investors and have several advisors so there's a kind of 'extended team'. We're looking to hire 3 people ASAP, so we'll soon be double the size.

Where are you based, how is it working there?

We're based at TechHub currently, I think Elizabeth Varley (TechHub CEO) set out to build a community not just an office space. She certainly succeeded. It's a very informal atmosphere, if you need some advice on anything from a bit of code to approaching top-tier investors, or even just a problem with your bike, there will be someone who can help.

Soon we'll move to White Bear Yard, another co-working space, which also seems like an excellent place to work. Passion Capital - one of our backers - is based there and we're keen to be close to them for a while.

As the team expands we think we'll look for own offices near near Old St, we want somewhere to call our own - maybe put up some wacky furniture and definitely keep a fridge well stocked with cheese and beer, plus we're considering getting a 3D printer to make physical visualisation of data. Wherever we end up we'll definitely keep our links with TechHub.

You're now hiring developers, what's the most important quality you look in a candidate?

It's hard to weigh qualities against one another, it's important to us that people are excellent at what they do, but we also want someone who gets excited about the massive impact our project can have.

How's a typical week for a developer?

Now is the most exciting time for someone to join OpenSignal because they can have a profound influence on the style of the company. We like to spend as much of our time as possible writing new code but there's a lot of other stuff that goes on, we're collaborating on some research papers with academics from various universities, we're producing reports that get lots of press attention. We'd love for our new hires to be multi-talented and multi-interested so while they'd focus on their speciality we want them to experiment with things - write some out-there code, maybe write blog posts.

We do a lot of things as a team apart from working. We sometimes eat lunch together, we often go to tech events together - we were at Dublin Web Summit last week which was exhaustingly fun. We're planning to have regular team events maybe some internal hack days, but also some laserquest!

Another thing we know works is to go and fly somewhere new and work from there for a week, so we'll take the team for weeks of hacking in places where the weather's fine, the food is tasty and the wifi signal is strong (we'll check our maps!).

What's the next challenge for OpenSignal?

We need to build an iOS app that will blow people away. We're also working on an advanced dashboard - a little like the maps on our website but with a deeper level of detail it will help networks make strategic, marketing and optimization decisions. For example, it's in no-one's interests for a network to market itself strongly in a place that it offers much poorer coverage than competitors.


OpenSignal is hiring.
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