Watch Dogs companion app out now and you don't even need to own the game

Ubisoft today released a free Watch Dogs mobile companion app for iOS and Android devices, allowing you to play with your friends on console or PC using your smartphone or tablet. The free app, called ctOS Mobile, lets you play with your friends across two modes: Race and Free Ride. In these modes, the console/PC player is pitted against the mobile player.

The console/PC player is trying to race from checkpoint to checkpoint (winning extra time for every checkpoint reached), while the mobile player sees the world from a top-down view and has the power to hack the city and thwart their opponent by triggering blockers or setting off explosions. Using the app, the mobile player can also attack opponents on a helicopter or even send the police to chase them down.

In the Race mode, the distances between checkpoints are shorter and the console/PC player has GPS turned on. For Free Ride, the distances are longer and the GPS is off by default. Across both modes, the mobile player wins if they are able to keep the console/PC player from reaching all the checkpoints.

To use the ctOS app, you'll need to log in with your Xbox Live, PlayStation Network, or Uplay account. The app does not require that you have Xbox Live Gold or PlayStation Plus, while Uplay is always free. You then enter your friend's ID and this person will appear in your feed, and you can invite them to join a match.

If your friends are all offline or if you'd rather player against a stranger, you can choose Quick Match, and the app's matchmaking system will find you a player who should be about your same level. The ctOS Mobile app also works across console generations, meaning you can use the app to play against players on Xbox 360, Xbox One, PlayStation 3, or PlayStation 4.

Your ctOS profile does not connect to console or PC, but it does have its own progression system where you can improve your skills and enhance your options as you gain experience. You'll also be able to unlock four different police units, increase your power to activate more hacks, and boost your helicopter skills.

For Watch Dogs players on console/PC, everything you earn while playing against a ctOS Mobile player--including experience and cash--will stay with your profile.

There are a total of 26 challenges in the ctOS mobile app, including 13 Races and 13 Free Rides, but that's not all. The app also includes a map generator, allowing you to create and customize elements on the map like where the starting point is, how many checkpoints there are, and how much time players have to reach them. You can also toggle the weather and time of day.

The ctOS Mobile app is out today and it's "completely, totally, 100 percent free," Ubisoft says. There are no in-app purchases or microtransactions. In fact, you don't even need to own Watch Dogs for console or PC to use the app.

Watch Dogs launched today across Xbox 360, Xbox One, PS3, PS4, and PC. The Wii U version is coming sometime later. The game is setting preorder records for Ubisoft and GameStop, and it's expected to sell more than 6 million copies. For more on Watch Dogs, be sure to read GameSpot's previous coverage.