marker.js

marker.js is a JavaScript library designed for developers who need to add image annotation features to their web applications. It lets users mark up images directly in the browser by adding text, arrows, callouts, emojis, and various shapes. This is useful for creating tools that require visual feedback, review processes, or collaborative editing on images.

The library is built as a set of headless web components, which means you can fully customize its appearance and behavior to match your app's design. It works with any modern JavaScript framework like React, Vue, or Angular, or can be used with plain HTML and JavaScript. Beyond the editor, marker.js includes separate components for viewing interactive annotations and for rendering the final marked-up images. You can start for free under a linkware license, which requires a small logo, or purchase a commercial license to remove it.

This tool is a practical solution for development teams building SaaS products, internal tools, or customer-facing applications where image-based communication is needed. Common use cases include building bug reporting tools where users can circle issues on screenshots, creating platforms for design feedback, or adding annotation features to document management systems.