The layoff decisions, which Amazon will communicate starting 18 January, will largely impact the company's e-commerce and human-resources organisations, he said.
The cuts amount to 6% of Amazon's roughly 300,000-person corporate workforce and represent a swift turn for a retailer that recently doubled its base pay ceiling to compete more aggressively for talent.
Its stock rose 2% in after-hours trade.
Jassy said in the note that annual planning "has been more difficult given the uncertain economy and that we've hired rapidly over the last several years."
Amazon has braced for likely slower growth as soaring inflation encouraged businesses and consumers to cut back spending and its share price has halved in the past year.
The company began letting staff go in November from its devices division, with a source telling Reuters at the time it was targeting around 10,000 cuts.
The tech industry shed more than 150,000 workers in 2022, according to tracking site Layoffs.fyi, a number that's continuing to grow.
Salesforce Inc said Wednesday that it planned to eliminate about 10% of staff, which numbered nearly 8,000 as of 31 October.
Reversal Of Fortunes
The reversal of Amazon's fortunes has been stark.
It changed from a business deemed essential during the pandemic for delivering goods to locked-down homes, to a company that overbuilt for demand.
Its layoffs now surpass the 11,000 cuts announced last year by Facebook-parent Meta Platforms Inc.
Jassy's note followed a report in the Wall Street Journal that the reduction would be more than 17,000 jobs.
He said that Amazon chose to disclose the news before informing affected staff because of a leak.
Amazon still must file certain legal notices about mass layoffs, and it plans to pay severance.
Jassy said, "Amazon has weathered uncertain and difficult economies in the past, and we will continue to do so."