Digit - the web app that basically serves as an automated savings plan - now has an iOS app for iPhone, iPad, and the Apple Watch.

Don't feel bad if you're completely incapable of setting aside money, because according to a tonne of recent studies, it's not common for Americans under the age of 35 to have any savings at all. But Digit hopes to change that.

It's a US-based service that launched last year. It monitors your spending habits, and when you can afford to, moves money from your checking account. You're still able to withdraw funds without being hit by fees, but the idea is that Digit will automatically figure out when and how much to save based on your lifestyle, allowing you to set aside for a rainy day.

The web app is simple. Just sign up on Digit's website to use the service, then connect your checking account, and allow Digit to analyse your income and spending. It transfers some money (usually $5 to $50) from your checking account to your Digit savings every two or three days. Until now, you had to send text messages via SMS to interact with the web app.

You could text "bills" to see upcoming expenses, "withdraw" to transfer money, etc. Now, however, you can use Digit's iOS app instead. It offers a keyboard with built-in Digit commands. You can tap the "+" icon next to the keyboard to see what Digit can do. You can also edit your profile. 

Aside from adding interest payments, the service hasn't changed much since launch. It is free and doesn't require a savings account at your financial institution. It works with over 2,500 banks and credit unions, comes with a no-overdraft guarantee, and uses "state-of-the-art" security measures. Also, the FDIC-insures all funds up to a balance of $250,000.

Digit uses 256-bit bank-level security and won't store your bank login. And as we mentioned earlier, you can use Digit to transfer money from your Digit savings back to your checking account. It allows unlimited, fee-less transfers.