ChangeProof: Compare PDFs

Compare PDF revisions without creating an account or uploading documents. Start with Version A and Version B, then keep later PDFs in the same local revision timeline and compare any two stored revisions. ChangeProof aligns pages, extracts embedded text, supplements image-only and uncovered scanned regions with on-device Vision OCR, and checks rendered page visuals. Large PDFs are processed progressively, with unchanged work reused from a bounded local cache. Review additions, removals, replacements, page changes, and visual differences in the draggable lens; mark each Pending, Expected, Flagged, or Ignored and add notes. Reopen local projects and export a redline PDF, CSV log, or JSON archive containing source hashes, revision lineage, comparison snapshots, review state, and limitations. No account, backend, cloud sync, analytics, advertising, tracking, external AI, or document upload. One paid download; no in-app purchases or subscriptions. Results assist review and do not guarantee completeness. Verify important revisions against the source PDFs.