Initiatives to revitalise the ailing Google Wallet programme were relegated to bit-part status at the Internet search giant's I/O developers conference in San Francisco last week, where the roll-out of a new Nexus tablet device took centre stage.

The reboot of the Wallet centres around the release of a new set of Save to Wallet' APIs designed to allow visitors to bank and merchant websites to save payment cards and offers to Google Wallet.

For merchants, the Offers component of the API allows customers to save coupons directly from the Web into Google Wallet for redemption at the physical store via NFC, mobile barcodes or by simply showing the offer code to the sales assistant.

The API for payment cards seek to make it easier for banks to load their cards into the Wallet. To date, only Citi has committed to Google Wallet, using an awkward back-end process that requires the bank to either issue customers with a new virtual credit card or open a pre-paid MasterCard account.

With the new API, issuing banks can either opt for a 'no integration' option, in which they supply card art and co-marketing to Google, or go for 'light' integration, which enables banks to push cards directly from their Websites into Google Wallet, with user consent.

At Google I/O, the firm demonstrated how Discover is working on a concept that would enable cardmembers to save their cards to Google Wallet from the Account Center at discover.com.

Google says it's testing the Save to Wallet API "with a few other bank partners right now", but has not disclosed the identities of the banks involved.

Separately, NFC World reports that Google reps have been spotted demonstrating Google Wallet to customers in central London department store Selfridges. Google has long been rumoured to be considering a launch of the Wallet in the UK ahead of the Olympics, which kick off in London later this month.