Proof of sent.

Every email the sending platform confirms is logged by its message ID, stored only as a hash. At the end of each UTC day the list is sealed with a fingerprint (SHA-256 of the sorted hashes). Download any day and recompute it yourself. Sealed days can never change.

Check it yourself

curl https://<this-site>/api/proof/2026-10-08 > day.json
node -e "const d=require('./day.json');const h=require('crypto').createHash('sha256').update([...d.messageHashes].sort().join('\n')).digest('hex');console.log(h===d.root?'MATCH':'MISMATCH')"