Privacy Policy

Sunday is a product of Main Street Group (“Sunday,” “we,” “us”). This policy covers the Sunday app — on the web at web3sunday.ai and in its iOS app — and this website, web3sunday.com. It does not cover other Main Street Group products, which publish their own policies.

Your account. Your name, your mobile number, and the display name and mail handle you choose. Your number is verified by one-time code and is how you sign in; we keep it because it is your account identity.

Your claimed addresses. The street, unit, city, state, ZIP and country of each address you claim, along with its normalized form, its map coordinates, and the identifier your CPiD is issued against. This is the point of Sunday: an address you control rather than one a broker has traded.

Your mail. Messages sent to your Sunday address — sender, recipients, subject, body, attachments, and delivery metadata. Attachments and raw messages are stored in encrypted object storage.

Your CPiD messages. The encrypted contents, the sender and recipient CPiDs, timestamps, and read state. See what we cannot read.

Payments and escrow. When someone pays to reach you, or you withdraw what you have earned, we record the amount, the currency, the status, and the identifiers our payment processor gives us. Card numbers and bank details go to Stripe directly and are never stored on our servers.

Contacts and circles. The CPiDs you have connected with, whether each connection is pending, approved or blocked, the private label you give a contact, and the groups you create and who is in them.

Technical data. Ordinary server logs — IP address, timestamps, and which endpoint was called — kept for security, abuse prevention and debugging.

CPiD messages are encrypted on your device before they are sent, using a key derived from a phrase only you hold. We store the resulting ciphertext and route it. We cannot decrypt it, and neither can anyone who compels or compromises us — there is no key on our side to hand over.

Two honest caveats. First, we can still see the envelope: who sent a message to whom, and when. End-to-end encryption protects contents, not the fact that a conversation happened. Second, a small number of older CPiD messages predate this design and are encrypted with a key our server holds. We are retiring them, they are labelled differently in the app, and we do not describe them as end-to-end encrypted.

Ordinary email is not end-to-end encrypted, by anyone. It arrives over the public mail system and we store it in a form we can read so we can show it to you and search it for you. We would rather say that than let the word “encrypted” do work it has not earned.

Ask Sunday answers questions about your own mail, wallet activity and contacts, and can group your recent inbox into sections. To produce an answer, we send your question and the specific items needed to answer it to Anthropic, which operates the model that writes the reply.

We send your question; and only the relevant items — for mail, the sender, subject, date and a short excerpt; for wallet activity, amounts and status; for contacts, names and identifiers. We do not send your whole mailbox. The request carries no account identifier, so the content is not linked to you at Anthropic.

Your encrypted CPiD messages are treated differently. They are searched on your device, and they are excluded by default. If you turn on “Also search my encrypted messages,” your device decrypts them locally, selects only the excerpts needed for that one question, and sends just those. With the setting off, nothing encrypted leaves your device.

We do not store your questions, the answers, or the excerpts. They exist for the length of the request and no longer. We keep counts — that a question was asked, and how many tokens it used — to measure cost and reliability. We do not keep the content.

Anthropic does not use data submitted through its API to train its models. Anthropic retains this content for a limited period for trust-and-safety purposes, after which it is deleted.

Claiming an address can require proving your identity. When you scan a driver’s licence, the image is read on your device and the image itself is never uploaded. We keep the result — that the name and address matched — together with your name and address. We do not store your licence number or your date of birth.

To deliver, display and search your mail; to route and price messages sent to you; to hold and release escrow; to verify address claims; to sign you in and keep sessions secure; to prevent fraud and abuse; and to answer the questions you ask Ask Sunday.

We do not use your mail, your messages or your address to build advertising profiles, and we do not sell your personal information. Sunday’s revenue is the toll a sender pays to reach you — that is the business model, and it only works if the data stays yours.

We share only what a provider needs to do its job, and only with providers who are contractually limited to that job:

• Amazon Web Services — sending and receiving mail, and storing messages and attachments.
• Stripe — payments, escrow and payouts, including the identity checks a payout account requires.
• Twilio — the one-time codes that verify your number.
• Resend — outbound message delivery.
• Google — normalizing an address you enter into a canonical one.
• Anthropic — generating Ask Sunday answers, as described above.
• Cloudflare — serving the app, and relaying calls when a direct connection cannot be made.
• Railway — hosting the Sunday API and its database.
• Vercel — hosting this website and its aggregate visit analytics.

We may also disclose information where the law requires it, or to protect someone’s safety. Where we can lawfully tell you, we will.

Mail and messages stay until you delete them or close your account. Payment and escrow records are kept for as long as financial and tax rules require, because they are accounting records. Server logs are kept for a short operational window.

A deleted CPiD message is recorded as delivered even after its contents are removed, so that certified delivery remains provable. The record is that it happened; the contents are gone.

You can delete your account from inside the app, under Identity. It removes your account and the data we hold for it, and it wipes the keys held on your device. Escrow and accounting records that we are required to retain are the exception, and they are kept without your message contents.

Depending on where you live, you may also have the right to access, correct, export or restrict the use of your personal information, or to object to certain processing. Ask us and we will do it.

Messages travel over encrypted connections. CPiD contents are encrypted before they leave your device. Sessions can be revoked everywhere at once, and the key that unlocks your messages on a device is held behind that device’s own biometric hardware.

No system is perfectly secure, and we will not pretend otherwise. If a breach ever affects you, we will tell you what happened, what was exposed, and what we did about it.

Sunday is not for people under 16, and we do not knowingly collect their information. If you believe a child has an account, contact us and we will remove it.

Sunday operates in the United States, and your information is processed there. If you use Sunday from elsewhere, you are sending your information to the United States, where privacy law differs from your own.

When this policy changes we will update the date at the top. If a change materially affects what we do with your information, we will tell you in the app rather than hoping you re-read this page.

Questions about this policy, or about your information: contact@msgpartners.io.