YouSaidThat lets you seal any prediction. A market call, a hot take, a thesis — with SHA-256 hashing, AES-256-GCM encryption, and RFC 3161 timestamps. No one can see it until you reveal it. Once you do, anyone can verify you wrote it exactly then, without trusting you or any platform. Built on open cryptographic standards. No accounts needed. Fully auditable. Your proof lives outside any server.

Hi everyone!! I built YouSaidThat because "I called it first" is impossible to prove after the fact. Screenshots get edited, timestamps can be faked. Reddit or X, even if are public, require an other layer of trust. So I made proof the default. You write a prediction, it's encrypted in your browser (the server never sees your text), and the decryption key is timelock-sealed with drand: it Literally doesn't exist until the date you pick. On top of that, a SHA-256 hash gets anchored on Bitcoin via OpenTimestamps plus an RFC 3161 timestamp. When you reveal, anyone can verify you wrote exactly that, exactly then, without trusting me, the platform, or any server. No accounts, fully open source, fully auditable. Two modes: Proof of Existence (prove you knew it now) and Sealed Prediction (lock it until a future date). Would Love your feedback, especially on the verification flow :)

The no-account setup and verifiable timestamping make this feel cleaner than screenshots or old posts. Curious how simple the reveal and verification flow feels for non-technical users.

yousaidthat.org

Prove that you said things before anyone else

Prove that you said things before anyone else