Pinterest just signed a check that would make most CFOs sweat. The company agreed to pay Amazon Web Services $4 billion for cloud services through 2031, marking its largest infrastructure deal ever and a clear signal about where the platform sees its future: deeply, irreversibly embedded in AI.

Wall Street liked what it saw. Pinterest shares climbed nearly 5% on the announcement, while Amazon’s stock ticked up about 1.7%.

What the deal actually looks like

The agreement extends a relationship that dates back to Pinterest’s founding in 2010.

The $4 billion commitment will fund access to AWS’s custom silicon technologies, specifically Graviton processors and Trainium chips. Graviton handles general computing workloads more efficiently, while Trainium is purpose-built for training and running AI models. Pinterest plans to use both to power visual search, content personalization, and generative AI features.