Show HN: Akashi Notari – On-chain Proof of Existence for any file in 60s for <$1

Hi HN, I built a simple tool to solve a problem I've faced as a developer and freelancer: how can you definitively prove a file (like code, a contract, or a design) existed at a specific time? It's called Akashi Notari, and it’s a simple utility for creating an on-chain "Proof of Existence." It lets you anchor any file's cryptographic hash on the blockchain (supports Base, Ethereum, Optimism). And costs less than a dollar. The main focus is privacy and simplicity: - *100% Private:* Hashing (SHA-256) is done entirely in your browser. The file never leaves your computer. Only the calculated hash is sent to the blockchain. - *Fast:* The whole process, from file drag-and-drop to a confirmed transaction, takes about 60 seconds. - *Verifiable:* As soon as the transaction confirms, you get a PDF certificate with the hash, timestamp, and a direct link to the on-chain transaction for verification. I built this as a "poor man's copyright" or a simple notarization tool for: - *Freelancers:* Proving when a deliverable was completed. - *Creators:* Timestamping IP (art, music, manuscripts) before sharing it. - *Anyone:* Timestamping contracts or records without the cost and hassle of traditional notaries. Maybe some commit-reveal scenarios. The workflow is just: 1. Drag/drop your file. 2. Connect a wallet. 3. Confirm the transaction. 4. Download your PDF certificate. 5. Prove anytime in the future that your file existed using simple instructions in PDF You can try it out here: https://akashi-notari.com/ https://akashi-notari.com/ You can also retrieve/verify existing certificates here: [https://akashi-notari.com/certificate-retrieval https://akashi-notari.com/certificate-retrieval](https://www.google.com/search?q=https://akashi-notari.com/certificate-retrieval https://www.google.com/search?q=https://akashi-notari.com/ce...) I'd love to hear what the HN community thinks!