One year after launch, fantasy sports platform DraftKings has closed a $7 million Series A round led by Atlas Venture to help it build out and market its mobile and Web offerings.

The funding comes as the startup has finished up a strong first year. It topped 1 million users on its Web and mobile platforms and claims the title of the “number one daily fantasy sports mobile app provider.”

At present, the company runs fantasy events for professional football, professional basketball, professional hockey, professional baseball, college basketball and college football.

DraftKings is on track to award out over $20 million in cash prizes during the 2013 fantasy baseball season. In addition to money, the company has also offered other rewards, such as a trip to the Super Bowl earlier this year.

CEO Jason Robbins said in a statement that the platform’s average user spends more than three hours per week and plays multiple sports.

“We were amazed to see how popular fantasy basketball became with our fantasy football customers, and we are now seeing similar conversion from fantasy basketball to fantasy baseball,” he said.

Real-money prizes online is hot stuff right now, and it’s only natural that these startups would attract their own real-money investors. Skillz recently launched a Android platform for cash tournaments in games of skill, and online poker just made a reappearance in the US with the arrival of Ultimate Gaming earlier this week.

Image credit: Thomas Northcut