Question: I need a plagiarism checker that provides detailed similarity scores and side-by-side comparisons with sources.

If you're looking for a plagiarism checker that offers detailed similarity scores and side-by-side comparisons with source material, Copyleaks is a top contender. The AI-powered service offers a range of products including a Plagiarism Detector, AI Detector and Codeleaks for finding AI-generated content, source code plagiarism and improving writing. Copyleaks checks for plagiarism in more than 100 languages and can be integrated with Learning Management Systems (LMS). It's also got data security and GDPR and SOC 2 and SOC 3 certifications.

Another powerful tool is Plag, which offers detailed reports that can help you verify the authenticity of documents. Its database is vast, with billions of articles, including scientific papers, and it checks for plagiarism in 129+ languages. Plag offers a range of scores, including similarity, plagiarism risk and paraphrase scores, and highlights passages that match so you can see what's going on. It also offers educator and student accounts, which is good if you're looking for a tool you can trust for academic and professional use.

If you need to check for plagiarism across multiple languages, Crossplag uses AI technology for a sophisticated system. It checks for originality across more than 100 languages and has an AI Content Detector. Crossplag offers a Similarity Report API for integration and a self-provisioning environment with tiered pricing. It's geared for individuals, schools and businesses, and protects data and intellectual property.