He said that, until this summer, OpenTable gave restaurants only “one blank box on the screen” to enter a wide range of information on a diner — such as dietary restrictions, preferred nights of the week and wines ordered — instead of separate fields that made it easy to see if a customer, say, has lactose intolerance.

“Not to be creepy, but instantaneous and easy-to-read customer data is the best way we have to give the customer the best service,” Mr. Kokonas said. “It lets us know that the last time you were here, you finished with a special spiced tea that you liked, and we can make that happen again and easily.”

Mr. Jampol of OpenTable said that his company also compiles piles of similar data on customers that restaurants could use — but that they rarely want it. “Restaurateurs have a lot of things to keep track of every day,” he said. “And as much as they say they want data, they’re often too busy to dive into it.”

Nonetheless, Mr. Kokonas and others see an opportunity to do it better. Tock, which was co-founded by Brian Fitzpatrick, a former Google engineer, spent roughly two years building its system, testing different components with restaurants and getting feedback. It is web-based rather than app-based, because that makes it easier for restaurants to log in and configure Tock to their needs.

Other new reservation services are also looking to please restaurants. Reserve has adopted an “open data model” that allows its restaurants to see what diners are looking for, and, since it tweaked it service in May, it is adding more than 100 restaurants a month (for a total of 850), said Peter Esmond, its vice president for customer success.

Say a potential customer is seeking a table for four at 7:30 p.m., and a restaurant is showing nothing available at that time. If it has a table available then that it has held back, it can quickly add it to its Reserve page in an effort to attract the booking.

Thus, more control over how reservations are made is put in the hands of restaurants, rather than the reservation app.