With a smartphone in your hand (and a good data connection), a city becomes something more. You can find new things to do, places to eat and people to see; you can unlock hidden gems in a city you've known all your life, or act like a local in a city you've never seen before; and you can travel around quickly. Don't underestimate speed. These are the apps the Guardian Tech Desk can't do without, in our own cities and others.
CityMapper
The product of an independent British developer, CityMapper puts the combined efforts of four transit agencies to shame. The app, which is available for London, New York, Paris and Berlin, uses public data to provide a best-in-class mapping app for getting you from A to B as quickly and cheaply as possible. As well as what you'd expect from a transit app – routes that cover all public transport, from buses to suburban rail; automatic re-routing in case of disruption; and an understanding of timetables that won't leave you shivering at a bus stop for 29 minutes having just missed the last bus for the next half-hour – it has an unmatched level of flair. From the ability to specify a "rain safe" route, keeping you underground and indoors for as long as possible, to a map of cycle-hire stations, with the number of bikes available at each marked up, it's getting hard to think of a service it doesn't offer.
Hailo
We aren't taxi-fiends, but sometimes public transport just doesn't do it. If you've missed the last train, failed to leave enough time to get to an appointment or are just extremely tired and emotional, sometimes throwing money at the problem can help. Hailo won't make taking a taxi hurt your wallet any less, but it does make the experience a dream. Open the app, hit the drunk-friendly big yellow button, and a driver will pick you up within minutes. Put your card details in it, and it even handles payment. Best of all, the same app works in 13 cities across six countries, earning its place in your holiday lineup too.
Foursquare
Foursquare has a bad reputation, earned during its heavily gamified early days. Yes, the app still asks you to check in to the places you go, and still awards you points for doing so – multiplied by going to the same place on consecutive days, or by checking-in with friends – but that's not really why you use it. Instead, think of it like a recommendation engine for the real world. Check into Foursquare enough, and turn on the mildly creepy tracking feature, and when you arrive in a new city (or just a new part of town) it will ping up recommendations for bars, coffee shops and restaurants based on where you've been previously. It's not always great (We probably didn't want to go to McDonald's in Paris, thank you), but when the personalisation works, it's worth it.
Ingress
Alternatively, perhaps the gamification of Foursquare appeals to you? Ingress takes that and dials it up several notches, turning the concept into an actual game. Your check-ins let you tap a "mysterious energy" flowing throughout the world and use it to aid one of two alliances: the "enlightened" or the "resistance". At its best, it encourages you to head off the beaten track, injecting a dose of serendipity in your everyday life. That park you went to to capture a node might turn out to be a lovely spot to sit with a drink, or a new route to work that avoids the traffic.
Line
It's no use knowing your way around a city if you have to do it all alone. Developed by Japan's Line Corporation, the basis of Line is instant messaging. Like WhatsApp and Viber, two other popular apps in its category, Line lets users send text, video and audio messages free of charge, as well as full voice calls. With 300 million users worldwide, 50 million of whom are in Japan alone, it's got a good case for being the worldwide messaging app, a title for which it will be fighting WhatsApp for some time. It's also inspired not one but two anime cartoons.
Square Wallet
The most niche app on the list, Square is only available in one country, and only widely used in one city, San Francisco. But if you're there, it's indispensable. Square itself is designed to let anyone accept credit card payments using just an iPhone. It's revolutionised garage sales and the like, and is well on the way to fulfilling the dream of a cashless society. But if you're in San Fransisco, it's the Square Wallet app you really want. It cuts the credit card out of the equation: just like with Foursquare, you check in at a location and then all you need to do to pay is say your name at the till. If you're a regular somewhere, it'll even check in automatically, letting you dispense with checkouts altogether. Though you still get charged, sadly.
London's Best Coffee
Blue Crow Media makes a number of apps that help very specific connoisseurs find their way around a city. As well as coffee apps for London and New York, it makes Craft Beer apps for the same two cities, and Burgerapp, which guides you to the best hamburgers in London. The editors of the apps take their task seriously. The Best Coffee apps make note of rosteries, espresso machines and brew methods, as well as more prosaic matters such as opening times, while the Craft Beer apps also include off-licences with a particularly strong selection, in case you fancy a night in. After all of that, if you fancy a bit of time offline, it also makes paper maps with the same information on – as well as a third coffee map for Paris.
