Websites using yup

About yup

Yup is a JavaScript schema builder for value parsing and validation. It's commonly used with form libraries to define validation rules in a declarative way.

Identifying yup in a website's stack reveals key decisions about its architecture, performance strategy, and development approach. Web Reveal automatically detects yup and hundreds of other technologies by analyzing page source, HTTP headers, and JavaScript signatures—giving you instant insight into how any site is built.

Why do websites use yup?

Teams choose yup because it fits neatly into modern workflows and solves real-world problems around performance, reliability, or developer productivity. Understanding which sites rely on it—and how widely it has been adopted—helps developers, marketers, and researchers make informed decisions when evaluating their own technology choices.

How does Web Reveal detect yup?

Web Reveal identifies yup by inspecting a combination of signals: JavaScript global variables and library fingerprints loaded in the page, distinctive patterns in HTML markup and meta tags, HTTP response headers such as X-Powered-By and Server, asset file paths and CDN URLs, and cookie names set by the technology. This multi-signal approach minimizes false positives and ensures accurate results even when sites obscure their stack.

What can I learn from knowing a site uses yup?

Knowing that a competitor or industry leader uses yup can inform your own architectural or vendor decisions. It also helps security researchers understand the attack surface of a given site, lets recruiters gauge a company's technical depth, and gives product teams data-driven insight into adoption trends across the web.

Frequently asked questions about yup

What is yup?

Yup is a JavaScript schema builder for value parsing and validation. It's commonly used with form libraries to define validation rules in a declarative way.

How can I check if a website uses yup?

Enter the website's URL into the Web Reveal scanner. It will instantly analyse the page and report whether yup is detected, along with every other technology in the site's stack.

Is yup widely used?

Web Reveal has already detected yup on a growing number of websites across different industries. Use the scanner to explore real examples and see how broadly it has been adopted.

What other technologies are commonly used alongside yup?

Scanning sites that use yup often reveals complementary technologies in the same stack—such as CDNs, analytics platforms, CMS solutions, and JavaScript frameworks. Run a scan on any of the sites listed above to see the full technology breakdown.