How Mailey works, in full

Mailey turns an email address into an on-chain account. The account exists before anyone signs up: it is derived, not created. Three things follow from that.

• You can pay someone who has never heard of a wallet.
• The recipient claims the account later, by proving the inbox is theirs.
• The account is an ordinary EOA, so it works in every wallet on day one.

MDS-1 maps a canonical inbox to a secp256k1 key. It is deterministic, stateless, and published so that answers from the resolver can be checked.

canonical = normalize(email)          // see "Normalization"
eid       = sha256(canonical)

for (let i = 0; ; i++) {
  const sk = hkdf("sha512", ROOT,
    "mailey/mds-1",                     // salt
    `acct:${canonical}:${i}`,           // info
    32);
  if (0n < toBigInt(sk) && toBigInt(sk) < SECP256K1_N) {
    return sk;                          // otherwise advance the counter
  }
}

account    = keccak256(pubkey(sk))[12:]
commitment = keccak256(`${eid}:${account.toLowerCase()}`)

Properties

• Pure. No database read is needed to derive an address.
• Portable. The output is a plain EOA — no factory, no proxy, no chain binding.
• Stable. One inbox maps to exactly one account, forever. There is no rotation.

Two spellings of the same mailbox must not produce two accounts. Normalization runs before derivation and is part of the standard.

Custom domains keep their tags because many teams route + addresses to different mailboxes. Folding them would merge accounts that different people control.

Authentication

Bearer keys, created in the developer console. Keys are shown once and stored hashed. Rate limit: 120 requests per minute per key.

GET https://mailey.app/api/v1/resolve?email=cfo@acme.com
Authorization: Bearer mk_live_…

200 OK
{
  "ok": true,
  "data": {
    "address": "0x7c3f…9a12",
    "canonical": "cfo@acme.com",
    "eid": "8f14e45f…",
    "commitment": "0x9ab3…",
    "derivation": "mds-1",
    "claimed": false,
    "self_custody": false,
    "chain": { "id": 4663, "name": "Robinhood Chain" }
  }
}

Session endpoints

• POST /api/auth/start — issue a code for sign-in, claim or export.
• POST /api/auth/verify — exchange a code for a session cookie.
• POST /api/send — transfer to an inbox or an address.
• POST /api/export — one-shot key release, requires a fresh export code.

September 2026

• MDS-1 resolver live on Robinhood Chain with published commitments.
• Key export with v3 keystore and one-way severing of hosted signing.
• Payment requests, contacts, audit log and scoped API keys.