Amazon is bringing thousands of jobs to Boston, but it isn’t the much-vaunted second headquarters yet.

The Seattle company will add 2,000 jobs in a new office tower in the Seaport — and get $55 million in tax and other incentives from the city and state — but it’s unclear what the decision means for Boston’s chances of landing Amazon’s massive second headquarters.

“Amazon is excited to create 2,000 more jobs in Greater Boston,” said Rohit Prasad, Amazon’s vice president and head scientist of Amazon Alexa, in a statement. “In just a few years, we’ve grown from a handful of software developers and scientists to a team of more than 1,200.”

The new building will be a 17-story office tower on East Service Road near Seaport Boulevard. Amazon will occupy the top 15 floors, a total of 430,000 square feet, when the building is finished in 2021.

Earlier this year, Boston development officials approved a $5 million tax break for the project, specifically tied to a pledge from Amazon to add 2,000 jobs.

The state has also agreed to pay up to $20 million in public infrastructure improvements in connection with the project.

The agreement with the city also included an option for an additional $5 million if Amazon decides to add an additional 2,000 jobs in a nearby building. Amazon declined to comment on whether they would exercise the option.

The company currently employs more than 1,200 software developers and researchers in the Boston area, and has said it will add 900 more at a new Fort Point office expected to be completed later this year.

“It’s great news for Boston that ​ Amazon is expanding its footprint in the Seaport, bringing new jobs and economic opportunities to our city,” Mayor Martin J. Walsh said in a statement.

The expansion comes as speculation continues over where Amazon will put its new $5 billion second headquarters. Boston and Somerville’s bids were selected as finalists for the economic development jackpot, along with Washington, D.C., New York City and 17 others.

Corporate relocation experts were split on how to read the tea leaves. John Boyd of the Boyd Co. said the announcement of a smaller office would make little sense if Amazon was getting ready to bring 50,000 new employees to the area.

“It’s a vote of confidence for Boston, but it does diminish its chances for the HQ2 process,” Boyd said.

But Thomas Stringer of BDO said the new office likely isn’t tied to the HQ2 decision.

“I think it’s separate,” Stringer said. “I certainly think it’s part of the strategy to make these announcements as beneficial to the company, as beneficial to the locations being considered.”