ProofDeed: Documents that prove they haven't been altered

Hi Product Hunt! I'm Scott, founder of ProofDeed — a veteran-owned startup from Oshkosh, Wisconsin. The problem I kept seeing: critical documents get tampered with after signing, and there's no easy way to prove it in court. Contracts, deeds, legal records — anyone with file access can alter them, and traditional signatures don't protect against post-signing edits. ProofDeed fixes this by taking a SHA-256 cryptographic hash of your document the moment you upload it and anchoring that hash to the Polygon blockchain. The result is a tamper-evident certificate that's admissible in federal court under FRE Rule 901 — permanent, verifiable proof that your document hasn't been altered since the day you created it. Use cases: real estate deeds, contracts, legal evidence, government records, compliance documentation. We're live and serving customers today. Would love your feedback!