Grubhub has created thousands of Web sites that masquerade as the sites of restaurants — a practice that can jack up prices for hungry customers, The Post has learned.

The online food-ordering giant, which also owns Seamless and Menupages, has scooped up more than 34,000 URLs since 2010 with names that are similar to restaurants’ own Web addresses, according to a database obtained by The Post.

In some cases, Grubhub creates a version of an existing restaurant site by changing a dot-com to a dot-net.

In all cases reviewed by The Post, Grubhub’s copycat sites use the restaurants’ logos — even as they direct customers to its Grubhub and Seamless sites.

While the duplicate Web sites typically have the same menu as the restaurants do, the prices can be higher than the prices customers would have paid if they had ordered from these restaurants directly, the data shows.

For example, all of the signature salads on Chicago Salad House’s Web site, www.chicagosaladhouse.com, cost $10. But on Grubhub’s dummy site, www.saladhousechicago.com, many of the same salads cost $11 or $11.25.

The Seamless Web site for 354 Steakhouse in Cliffside Park, NJ, charges $7.95 for onion soup, or $1 more than the restaurant itself charges, while the 26-ounce porterhouse for one costs $43.95 via Seamless — or $2 more than the restaurant’s actual price. 345 Steakhouse confirmed its lower prices when contacted by The Post.

“There’s certainly ethical questions,” Andrew Rigie, executive director of the New York City Hospitality Alliance, told The Post. “Even if there is language in the contract, I suspect many restaurateurs don’t understand what it means: That they are losing control of their business.”

Grubhub said in a statement that it only created domain names for restaurants “as a service” to them — a practice it has since stopped. “It has always been our practice to transfer the domain to the restaurant as soon as they request it,” the company said.

Ahmet Bugdayci, the owner of Abracadabra Magic Food in Williamsburg, said he asked Grubhub for domain name Abracadabrabrooklyn.com — which he discovered the delivery service giant had taken when he was trying to build his own site roughly five years ago — only to give up because the process was too complicated.

“In the beginning, we asked. It’s not easy,” Bugdayci said. “This is what they do, you can’t do anything. We want to talk, but it seems like a long process. We are a very small business.”

In a Google search for Abracadabra Brooklyn, Grubhub’s doppelganger page — along with the official Seamless and Menupages sites — appears before Abracadabra’s actual Web site.

A database created by a private investigator and researcher shows 34,504 Web sites registered with copycat Grubhub URLs since 2010, according to a copy of the document obtained by The Post.

A separate database created by the same researcher showed that more than 9,158 of the copycat URLs are still active. Some of the restaurants whose Web sites appeared on the list have their own proprietary online ordering system, like Chicago Salad House, the researcher noted.

The wannabe sites appear legitimate until a customer scrolls to the very bottom, down past a menu and about 10 of the latest reviews. There it mentions a Grubhub Holdings copyright.

The sites even include Grubhub-registered phone numbers (different from a restaurant’s own real phone number) that record the calls and charge restaurants a commission, according to sites viewed by The Post.

Complaints about the sites first surfaced at a New York City Council hearing last week, in which Grubhub executives denied any knowledge of alleged “cybersquatting.”

“I’ve never seen any evidence of cybersquatting or copying of restaurants to take their business,” Sami Naim, Grubhub’s director of public policy, said at the hearing. “None whatsoever.”

Grubhub in a statement said it “has never cybersquatted,” which it defined according to a nonprofit internet think tank as a “generally bad faith registration of another person’s trademark in a domain name.”

The revelations come after The Post first exposed that the delivery company was registering thousands of dummy phone numbers for restaurants in order to take commissions on phone calls.