Back in March, just before SXSW, Foursquare announced a partnership with American Express that would see card users getting discounts, by checking in at stores, restaurants, etc. They began testing in Austin, where those who linked their AmEx and Foursquare accounts could spend at least $5 at a local merchant, and get a $5 savings applied to their monthly statement.

“When we launched, the response was overwhelmingly positive. So, after SxSW, we sat down with American Express to plot the future,” writes Foursquare Director of Business Development Tristan Walker on the Foursquare blog. “Today, we’re happy to announce that the partnership is going national. Across the whole country, at select merchants, you can now check-in with foursquare, pay with your American Express card, and get big savings on your monthly statement.”

“Our national launch with foursquare reflects our continued focus on digital innovation aimed at bringing value to cardmembers and merchants where they’re already engaged and focused,” says Ed Gilligan, Vice Chairman at American Express. “The success of our pilot just a few months ago proved that American Express’ digital capabilities and foursquare’s expanding application created something extremely powerful. We’re thrilled to take this partnership to the next level. For us, this is just the beginning.”

“Partnering with American Express to offer Specials to their millions of cardmembers on a nationwide basis not only allows us to provide a completely seamless redemption experience to both users and merchants, it also enables merchants to really measure the success of their offline marketing efforts with foursquare,” said Foursquare CEO Dennis Crowley. “The load-to-card functionality of the Smart Offer APIs provides the millions of American Express merchants with an effortless way to serve up Specials to our more than 10 million users.”

At SXSW, we interviewed Foursquare Director of Business Development Eric Friedman, who talked about the partnership a bit (while Crowley played an actual game of Foursquare in the background):

Foursquare CEO Dennis Crowley retweeted this:

To take advantage, simply link your accounts, check in at participating stores and tap “load to card” on the Special in Foursquare, and pay with your AmEx card. They’re kicking off the launch with stores H&M (where you can spend $75 and get $10 back) and Sports Authority (where you can spend $50 and get $20 back). On the Foursquare blog, they also talk about several New York restaurants who are already offering specials.

Earlier this week, Foursquare announced that it’s surpassed 10 million users.