Citibank has launched its digital wallet called Citi Pay, which allows Citi customers to quickly pay for goods and services online, in-app or in-store.

The service was first rolled out in Singapore, Australia and Mexico last November, and it included tap and pay capabilities. It's launching in the U.S. a little later than the "early 2017" it expected.

"Whether it is online, on a phone, or at a store, we want Citi customers to have seamless, convenient and fast payment options wherever they go," said Barry Rodrigues, head of global digital payments at Citi, when the service launched last year. Rodrigues also touted the wallet's ability to offer payment flexibility.

Citi Mastercard customers can take advantage of the digital wallet service, which takes a credit card number and tokenizes it, or turns into a unique digital number. When you pay, the merchant gets your tokenized number and never has access to your actual credit card number. This step adds a layer of protection to your card, so if a criminal hacks into a website you're shopping from or a store where you're using a credit card, the tokenized number will be useless to the thief.

Citi Pay also makes online shopping faster because you can shop with your existing Citi login. That login saves your shipping and payment information--up to six addresses--so you can check out more quickly. All eligible cards become linked to your Citi login, so you don't have to type in your card number every time you make a purchase either. When your card information changes, the digital wallet automatically updates with the current information.

Citi Pay is accepted online wherever you see the Citi Pay or Masterpass logo, which is accepted at thousands of well-known retailers, including Walmart, Shutterfly and Dunkin' Donuts. You can activate Citi Pay when you click on the Citi Pay or Citi Pay Masterpass button during the checkout process.

In stores, Citi Pay leverages NFC technology found on Android phones to enable tap and pay transactions at checkout. To use it, unlock the app with a PIN and hold your phone near a payment terminal that's enabled for contactless payments. This triggers the tokenization process, which also masks your card number, when you make a payment. Many retailers like Panera Bread, Toys-R-Us and Walgreen's accept contactless payments.

The digital wallet also comes with Citi's protection benefits, including zero liability on unauthorized transactions, damage and theft purchase protection, extended warranties, Citi Price Rewind, and special access to special event ticket purchases.

The Citi Pay app is fairly easy to set up, if you already have a Citi online account. It requires a text or call confirmation, as well as access to calls and location, as a fraud protection measure. You can even set up biometric authentication with a fingerprint to open the app more quickly. It also stores loyalty cards, gift cards and prepaid cards so you can keep them handy for use when shopping; however, it doesn't provide a running balance for the dollar amount that's actually on each gift card. If you have a drawer full of partially used gift cards, this digital wallet will just provide a place to store the card identification information.

While the in-person contactless payment feature is only available for Android phones, you can use Citi Pay on Apple devices, though it looks like you do that simply through a web-based interface and not within an app.

Citi Pay is exclusively only for Citi Mastercard consumer credit cards. Those with Citi Visa cards, American Express cards or Costco Anywhere Visa Business cards can't use the full features of the Citi Pay digital wallet, but they can still use the Masterpass feature for online shopping.