Boston’s Amazon HQ2 consolation prize is officially underway.

Massachusetts Gov. Charlie Baker and Boston Mayor Martin Walsh joined WS Development and Amazon Tuesday for the groundbreaking of what will be the Seattle-based company’s most prominent office in Greater Boston.

The glassy, 17-story, 525K SF Seaport Square building at 111 Harbor Way is expected to house 2,000 Amazon workers.

News of the Seaport Square deal spurred national speculation it was the first phase of Amazon HQ2 when plans of the office leaked during the second headquarters sweepstakes.

Northern Virginia eventually won out for HQ2, but Boston doesn’t appear to be losing any sleep over winning a smaller office.

“It’s worth noting that the only time that Boston has grown at a faster pace than we see today might have been in the wake of the vast urban renewal programs two generations ago,” WS Development Senior Vice President Yanni Tsipis said at the groundbreaking. “Now today, we are fortunate that we didn’t have to knock down a big part of our city to realize this pace of growth.”

Amazon’s new office is expected to generate nearly $4.5M in funds for affordable housing as well as $875K for technology job training. Amazon will get $5M in municipal tax breaks for hiring 2,000 people by 2025. It would be eligible for more tax dollars if it exercises an expansion clause in its lease for a second building next door that could bring the Seaport employee count to 4,000.

“The project benefits everyone in the city of Boston,” Walsh said.

Amazon currently employs about 4,500 in Greater Boston and opened a 900-person office earlier this year in Fort Point near 111 Harbor Way. It also has a large presence in Kendall Square, and Amazon is expected to open a 1,500-worker distribution center in North Andover.

Close to 750K SF of office is currently under construction in the Seaport, and Amazon’s new office will push the neighborhood’s office inventory to 11.8M SF. The Seaport’s office inventory alone has increased by 43% since early 2010, according to Hunneman Director of Research Liz Berthelette.

Another five projects planned for the neighborhood, including MassMutual’s 315K SF Fan Pier office building and WS Development’s 475K SF 88 Seaport Blvd., would add close to an additional 2M SF of office space in the neighborhood.

“The groundbreaking of Amazon’s new Seaport office is one more project in a long list of new developments that have completely transformed this submarket,” Berthelette said.

It is also the latest in a string of developments critics say aren’t doing enough to improve the public realm of the waterfront neighborhood, accusations WS has denied.

At a Bisnow event earlier this year, Tsipis highlighted how Seaport Square will include Harbor Way, a linear park to connect Summer Street all the way to the Boston Harbor ferry terminal. He was not made available for a follow-up interview in time for publication of this story.

Tuesday’s groundbreaking also means construction begins on the 1.5-acre Harbor Square Park, which will be integrated into the Harbor Way.

“This unprecedented growth is not just changing the city’s skyline — it is also creating a new public realm in our neighborhoods and along our coastline unlike anything the city has seen since the days of Olmstead,” Tsipis said Tuesday.