Inputs.io is a free Bitcoin eWallet that leverages it's own off chain payment network. Inputs is one of the most secure web wallets on the market, with two factor authentication, location based email confirmation, client sided hashing, and a setup that prevents the hack of Bitcoins even if the web server was compromised.
Transactions between Inputs users and merchants carry no fee, no double spending risk, and confirms instantly. The API to integrate with Inputs is also much easier to implement, and there are no fees. Payment buttons allows frictionless payments without the visitor having to leave the merchant's webpage.
Currently, Inputs.io is supported by the following sites:
Just-dice.com BitsPoker.com CoinLenders.com Coinchat.org
Inputs.io is also a Bitcoin Foundation Silver member.