Copyscape catches byte-level plagiarism. It misses paraphrased near-duplicates. This tool computes cosine similarity on BOTH word-frequency and shingled-phrase fingerprints, catching the semantic overlap Google's systems see. Optional path to use a real embedding API (OpenAI, Voyage, Cohere) with your own key — key never leaves the browser.
Read the story behind this tool: Byte-level plagiarism detection misses the overlap that hurts rankings →
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