One POST request gets you a score, a verdict, the sources that matched, and the exact passages to highlight. Here's how to build it into a real product.

If your app accepts writing from users, sooner or later someone asks whether that writing is original. It might be an LMS that takes essays, a CMS where freelancers submit articles, a marketplace for guest posts, or an internal tool where an editor reviews drafts before they go live.

Building plagiarism detection yourself means crawling and indexing the web, fingerprinting text, and matching passages at scale. That's a company, not a feature. A plagiarism checker API lets you skip all of it: you send text, and you get back a score, the matching sources, and the passages that matched.

This guide uses the Proofademic API , which added a plagiarism checker alongside its AI detector in July 2026.…