Republic Wireless and Google's Project Fi both support the Google Pixel and Pixel XL smartphones. These are two Wi-Fi hybrid networks, that offer a cheaper alternative to consumer's phone plans. These services will seamlessly shift a user's phone service between cellular and Wi-Fi when needed. So when a Wi-Fi connection is available, the phone will utilize it to save costs. This can also improve the call sound quality, especially in areas where there is a limited carrier coverage, but there is a good Wi-Fi signal.
Both Project Fi and Republic Wireless have their cons and pros and their prices differ. Project Fi, for example, asks $10 per GB but charges for roaming fees. For using cellular roaming will cost you $60 for 4GB. Price may change, so check out the official websites for updated rates.
Republic Wireless offers several packages. The most basic package costs $15/mon and offers unlimited talk, text and Wi-Fi data transfer (not cellular data), which is a solid deal for those who need data for cellular roaming and cheaper than Project Fi. Other packages: include $20/min for 1GB and $30/mon for 2GB, $45/mo for 4GB, $60/mon for 6GB of cell data and their most expensive package cost $90 for 10GB of cell data. As I mentioned, the prices and data transfer volumes can change, so visit those company's website to see the latest prices and offerings.
Project Fi has another significant advantage of working with a wider range of cellular network providers: T-Mobile, Sprint, and U.S. Cellular, while Republic Wireless only support Sprint Network.
The great thing about these services is that there are no overcharges and hidden fees and they can really reduce the price that you pay compared to what you get from your current cellular service provider. Project Fi even credit you in money fo unused data, so customers pay only for the amount of data they consumed, not a fixed fee for a pre-selected data transfer volume. There is an online calculator on Project Fi website that shows you how much you can save if you'll be credited for an actual usage compared to your current data plan.
These services are very good for people who don't consume a lot of cellular data, those who travel abroad and those who want to reduce the total cost they pay for wireless connectivity. Some people will be better off getting a prepaid card instead, depends on your specific needs.
So both the Google Pixel and Pixel XL are supported by these two services. For the list of all compatible devices, visit the official websites at republicwireless.com and fi.google.com.