Google will start making its Android Pay service available today, according to multiple sources, as the search giant prepares to take another stab at mobile payments. The company plans to roll out availability to some users every day for the next seven days, according to these people. It’s not clear if the service will be made available through an update of the Android operating system or by downloading a separate Android Pay app.

Google spokespeople didn’t immediately respond to a request for comment.

Google was the first of the big mobile companies to let people tap and pay with their phones in stores when it released its Google Wallet service back in 2011. But that service failed to build a large user base in part because not many stores had the equipment necessary to accept the payments and in part because some of the big phone carriers like Verizon and AT&T blocked it from their phones as they tried to build a competing service called Softcard. It also wasn’t clear whether many people found it easier to use their phone to pay instead of a credit card or cash.

But the introduction of Apple Pay last year re-ignited interest in mobile payments among credit card companies, banks and some retailers, pushing Google to go at the market once again. Google ended up acquiring technology from Softcard, which shut down its own app, and cut a commercial deal with the carriers before announcing its Android Pay initiative in the spring. Samsung recently announced availability of its own service, Samsung Pay, too.

Like Apple Pay, Android Pay will let people tap and pay with their phones at stores that have a certain type of checkout equipment including a technology known as NFC. While only a fraction of retail stores have the equipment today, the numbers are expected to grow quickly over the next few years as U.S. stores are pushed to upgrade equipment to accept new, more secure types of “chip” credit cards. Best Buy, Macy’s and McDonald’s are among the chains that will accept the payment method, according to the Android Pay website.

Android Pay will also be a payment option in some Android apps, like Apple Pay is on some iOS apps. Chipotle, Etsy and Groupon are listed as partners.

With the move, Google has refashioned Google Wallet as a money-transfer app, where it will go head to head with apps such as Venmo, Square Cash and PayPal and services embedded in Facebook Messenger and Google’s Gmail.

Update: Google made it official. In a blog post, the company said it was beginning the roll out of Android Pay, which will work with all major carriers, credit card companies and banks. More banks, store locations and features will come later.

“Mobile payments is an important area for Google, and this is just the beginning for Android Pay,” Pali Bhat, director of product management for the feature, said in a statement. “We have a great set of partners that have contributed to the launch of Android Pay, and we’ll continue to work closely with the entire ecosystem to make paying with your Android phone simple, secure, and available everywhere.”

Google also officially rolled out the Wallet app, for both Android and iOS. Right now, it only provides payment transfers, but Google said it will have more news “soon.”

Contributing reporting by Mark Bergen