CaptionCrawler is a browser extension developed by Microsoft Corporation. It is a free program available on the Chrome platform, categorized under Browsers and Add-ons & Tools.

CaptionCrawler is designed to add captions to images that do not have any, specifically for screen-reader users. The extension retrieves captions from other web pages that contain the same image. If there are multiple available captions, users can navigate through them using keyboard commands.

Developed as a research project by the Ability Group at Microsoft Research, CaptionCrawler aims to improve accessibility and enhance the browsing experience for individuals who rely on screen readers. With this extension, users can now have access to image descriptions, making web content more inclusive and informative.