OpenTable is starting to see a lot more reservations coming from mobile, but the big hinderance to even more adoption is that not many restaurants have a mobile-friendly version of their Web site.

The online reservations company is hoping to solve that problem by giving restaurants the tools they need to optimize their sites for the smaller screen.

Starting today, OpenTable will be reaching out to thousands of restaurants regarding the free service, which will be powered by its partner, DudaMobile. But if restaurants don’t act fast, OpenTable will start charging around $100 for the service after Jan. 31.