Microsoft and Walmart couldn’t have picked a better day than Amazon Prime Day to announce a partnership that will compete directly with AWS (Amazon Web Services).

Amazon competitors like Walmart and Target are not keen on the idea of their own developers relying too much on AWS. Last year, there were reports that Walmart asked it’s developers to stop using AWS and move to Azure.

Their skepticism is not misplaced. Amazon is not known for playing nice with competitors. Amazon stopped selling Apple TV and Google Chromecast from its online retail store.

Now, Walmart and Microsoft are aligning forces to compete with AWS. The two companies forged a 5-year partnership with Microsoft as its preferred and strategic cloud provider. Walmart will be using the full range of Microsoft cloud solutions, including Microsoft Azure and Microsoft 365 for enterprise-wide use to standardize across the company’s family of brands.

“As part of the partnership, Walmart and Microsoft engineers will collaborate on the assessment, development, and support phase of moving hundreds of existing applications to cloud native architectures. For example, to grow and enhance the online experience, the company will migrate a significant portion of walmart.com and samsclub.com to Azure, including its cloud-powered check-out, enabling Walmart to grow with rising customer demand and reach more global markets than ever before,” said Microsoft in a press release.

This partnership may not be a major blow to AWS, which maintains a massive lead over both Microsoft and Google in the public cloud space, however, it’s the beginning of a long fight where Amazon competitors will be tempted to align with Microsoft and Google.