Picture this

Who it is for

Funmi writes a letter to each of her children and stores the deed to the family plot. Sealed Letters keeps them encrypted, asks her to check in every month, and opens each letter only to its named reader if she stops.

Two ways to own it

What you get

Base$189

$47 deposit to reserve

Encrypted upload to Walrus, Seal policy contract, check in reminders, reader unlock page.

You choose: check in period
You choose: accent color

Customfrom $1,500

Built around you

Reshape it entirely: new features, your flows, your brand end to end, integrations you need. We scope it with you.

Everything in Base
Custom features and design
Priority build

Why it is new

What exists today, and what this does differently

What is new

Search found no inheritance or dead man's letters app on Seal and Walrus; Mysten's launch post lists time lock uses only in general.

Closest things out there

Seal (Apple CloudKit inheritance app, unrelated); Mysten Seal examples.

Checked with web searches in October 2026. A search is not proof that nothing similar exists, and the market moves fast, so we recheck before every build.

What it unlocks

The human in it

Words that reach the right person at the right time.

The Regatta Board

Races it can enter

grant · Sui Foundation · rolling

Sui Foundation Grants

rolling

Official page ↗

Ecosystem program for shipped apps; check current terms.

Their rule on existing code: Existing projects OK

What you own

The whole app, not a starter kit.

The complete Sealed Letters app: writers leave letters and papers encrypted on Walrus, check in with one tap, and a Seal rule on Sui opens each one only to its named reader if they go quiet, with a paywall and USDC checkout built in.

Base price · $189

The user app, complete

Every buyer gets the same finished app. Basic branding and copy changes come through a quick form.

Three step onboardingHome

Shown once: write it now, tap to say I am here, they read it only then.

One tap check in from HomeHome

Days until the next check in, streak, release day and the primary I am here button.

Letters and documents per readerLetters

Write letters, scan documents or a password list, each named to one reader, drafts stay on the phone.

Seal flow with receiptsLetters

Encrypt on the phone, upload to Walrus, write the Seal rule on Sui, then a receipt.

Silent editsLetters

Change readers, add lines or remove letters without anyone being told. Extra letters gated behind Family.

Check in clock and Sunday linesClock

Drawn timeline of period, grace, guardian window and pause, with one line added per check in.

Short period warningClock

Warns when a short clock with no guardian could open letters during a hospital stay.

Reminder channelsClock

Push for everyone; WhatsApp and SMS gated behind Family.

Guardian who can pause, never openGuardian

Aunty Bisi confirms she is alive and pauses release. Gated behind Family; second guardian on Estate.

The quiet testGuardian

Simulate a check in, a hospital stay, going quiet, or a reader asking for the wrong letter.

Reader page previewGuardian

What the reader sees: nothing before release, then their own letter with Google sign in.

Onchain receipts and storageReceipts

What is on Sui, what is on Walrus, what is never anywhere, plus storage renewal.

Plans, share card and settingsMe

Pricing from the owner paywall with USDC checkout, share card, permissions and vision.

Open the full app demo

Add-on

Owner console

Your admin side: revenue, paywall editor, users, rules and the agent log.

Revenue and paywall editorRevenue

MRR, payouts, incoming USDC payments, accepted methods, live editing of tiers, prices, free letters and gates.

Rules, agent log and roadmapRules

Minimum period, grace, guardian window, pause length, fallback, gas, warnings, renewals; plus the Agent log and priced Roadmap.

Top-up

Growth and referrals

Referral and growth mechanics, switched on when you are ready to grow.

Growth loops and cohortsGrowth

Family group invites, readers becoming writers, guardian invites, referrals and cohort retention.

The money path, built in

How it earns for you

The first letter is free forever. Families pay monthly for more letters, a guardian and reliable reminders; Estate is a yearly plan that prepays storage. Payments arrive in USDC.

KeepsakeFreeOne sealed letter, one reader, push reminders

Family$4 a monthUp to 10 letters and documents, a guardian, WhatsApp and SMS reminders

Estate$49 a yearEverything in Family, two guardians, storage paid years ahead, a printed reader guide

Check in gas (a fraction of a cent) and Walrus renewals can be sponsored by the owner. Reminders cost about $0.01 each.

Prices are yours to set. Illustrative, not a promise of income.

Growth loops, built in

How it spreads

Readers become writers: every opened letter carries a quiet note that someone you love used this
Guardian invites: each writer brings a guardian who often writes their own letters
Family group invites shared in diaspora WhatsApp groups
Writer to writer referral codes worth a free month for both
Share card after sealing: I wrote the letters I could never say out loud

Roadmap · build the next phase with us

Where it goes next

v1 included

The writer app

Letters encrypted on the phone, stored on Walrus
Seal policy per reader with a check in clock
Guardian pause, quiet test, reader page
Reminders with channel fallback, receipts
Paywall with USDC checkout

Included

Voice, video and birthday letters

Voice notes and short video letters
Letters that open on a birthday or wedding day
Two guardians with a shared pause
Storage renewals paid decades ahead

Add-on from $400

Wallet and account handover

Hand over wallet access by the same rule
Account checklists for banks and phones
Lawyer and notary partner portal
Printed reader kit for older relatives

Add-on from $900

For investors and grant reviewers

The pitch, ready

Letters that open only to the person they are for, and only if you go quiet.

Problem: Letters, deeds and family passwords sit in drawers or cloud accounts nobody can open. Families abroad find out too late, or the wrong relative finds them first.

Solution: Writers encrypt on their phone, store on Walrus, and a Seal policy on Sui releases each letter to its named reader only after a check in clock and a guardian confirm the silence is real.

Why now: Seal and Walrus make private, rule based release practical, and zkLogin plus sponsored transactions let people with no wallet use it.

Market: Older parents with children abroad, diaspora families, and anyone with words or papers that must reach one person.

The ask: Pilot partners among diaspora community groups and churches, and a Sui Foundation grant.

Funding is never guaranteed. Check each program's rules.

For hackathons and demo days

Your 2 minute demo

Home: meet Funmi, 63, in Ibadan, with letters for Tolu in Toronto and Kemi in Nairobi.
Letters: seal Kemi's letter, hit the free limit, and unlock Family through the USDC checkout.
Clock: check in after church and add a Sunday line; try a 30 day clock and see the warning.
Guardian: run the hospital path, Aunty Bisi says she is alive, release pauses.
Guardian: let Kemi ask for Tolu's letter and watch Seal refuse it.
Receipts: show what is on Sui, what is on Walrus, and what is never anywhere.
Owner Revenue: change the Family price and free letters, then preview the Plans sheet.
Owner Agent and Roadmap: turn off fallback to see the failure, then request voice letters.

Many hackathons require code written at the event. See the Regatta Boardfor each race's rule.

Make it entirely yours

Custom work from $1,500: your own languages, a church or community branded deployment, extra reader types, or integrations with a lawyer's case system. Scoped on a call.

Custom from $1,500

BLUEPRINT

Why it matters and how it really works

The need

Most people have words and papers that should reach one person if they die or go missing: a letter to a child, a land deed, a password list for the family. Today these sit in a drawer, with a lawyer, or in a cloud account nobody can open. Families abroad find out too late, or the wrong relative finds them first.

What exists and what is new

Pieces exist. Mysten's Seal is a live decentralized secrets management service on Sui with example access policies, including time locks, and Walrus stores encrypted blobs. Web2 dead man's switch and digital legacy apps exist, and an unrelated Apple CloudKit inheritance app is also called Seal. Our search found no inheritance or dead man's letters app built on Seal and Walrus; Mysten's own launch post mentions time lock uses only in general. What is new here is the product: per reader letters, a check in clock the writer controls, a guardian who can pause but never open, and a reader page for people who have never used a wallet.

The data it runs on

Encrypted letter and document blobs on Walrus, a Seal access policy object on Sui holding each reader's address, the check in period, grace days and guardian, the last check in time, guardian pause events, and reminder delivery status kept by the app. Plain text never leaves the writer's device.

1.The mission

Let anyone leave the right words to the right person, kept private until the moment they are needed, without trusting a company to keep a secret.

2.Why people can't resist it

One tap of calm A monthly or weekly tap says I am here. It takes a second and it is the whole product working.

Sunday lines Each check in can add one line to a letter. Over a year that becomes the letter you actually wanted to write.

Nobody can peek Not the app, not the guardian, not a sibling. Readers learn a letter exists only when it opens to them.

3.How it works for real

Write and encrypt: The writer composes letters or uploads documents in the app. Each file is encrypted on the device with the Seal SDK, using an identity tied to the policy object and the named reader.

Store on Walrus: The ciphertext is stored as a Walrus blob for a chosen number of epochs. Only the blob ID is kept in the policy.

Policy on Sui: A small Move package defines the policy: reader address per letter, check in period, grace days, optional guardian and guardian window. Its seal_approve function lets key servers release key shares only when the clock is past release and the caller is the named reader.

Check ins: Each check in is a sponsored Sui transaction that resets the clock. Writers sign in with zkLogin, so a Google or Apple account is enough.

Reminder agent: A scheduled worker sends push, WhatsApp or SMS reminders through the grace window, falls back to a second channel on bounce, and asks the guardian before release. It holds no keys.

Guardian pause: The guardian can sign one pause per period that extends release by a set number of days. The guardian cannot open, read or shorten anything.

Reader page: After release, the reader signs in with zkLogin, Seal key servers check the policy, and the letter decrypts in the reader's browser.

4.Cost per use and pricing

Walrus storage for a few small letters and a scanned deed (under 10 MB) is typically well under a dollar a year at current prices. A check in is a single small Sui transaction, usually a fraction of a cent, and can be sponsored. Reminders cost about $0.01 per SMS or WhatsApp message. Example: 1,000 writers checking in monthly with 3 reminders each is roughly $40 to $60 a month in messaging and gas, plus storage renewals. All figures are estimates and move with token prices.

Keepsake Free

One letter, one reader, 90 day check in, push reminders.

Family $4 a month

Up to 10 letters and documents, any period, WhatsApp and SMS reminders, one guardian.

Estate $49 a year

Larger documents, two guardians, multi year Walrus storage paid ahead, and a printed reader guide for older relatives.

5.Growth loop

Every opened letter comes with a quiet note: someone you love used this. Readers often become writers. Writers invite their guardian, and families add each other. The Sunday line habit keeps writers active, and diaspora communities share it in family groups.

6.Risks and guardrails

Opening while alive: A short period with no guardian can release letters during a hospital stay. Default to 60 days plus a guardian, and show the writer the risk clearly when they choose shorter.

Key server trust: Seal uses threshold key servers. If enough servers collude or go offline, privacy or access can suffer. Use independent servers and explain this plainly.

Storage expiry: Walrus blobs are paid for a number of epochs. The app must renew ahead of expiry and warn writers well before.

Not a legal will: A letter or deed scan does not transfer property by itself. Say so, and suggest a lawyer for estate matters.

Coercion: Someone could pressure a writer to add them as reader. Allow silent edits at any check in and never notify readers of changes.

7.Build order

Move policy with reader, period, grace and seal_approve
Client side Seal encryption and Walrus upload
zkLogin sign in and sponsored check ins
Reminder worker with push and WhatsApp fallback
Guardian pause flow
Reader unlock page

8.Where this is going

Now
Letters and documents on Walrus, opened by a Seal rule on Sui only to the named reader after a writer goes quiet.
Next
Two guardians, voice notes and video, renewals paid ahead for decades, and letters that open on a birthday.
Later
Handing over access to wallets and accounts, with the same rule, so families do not lose what was meant for them.
The world it builds
Last words that cannot be lost, read early or kept by the wrong person.

Costs and tools are estimates at the time of writing. General information only, not legal or financial advice.

OWNER PLAYBOOK

Own it, then chart your voyage

Nine routes from one vessel. Tap a port to open its chart.

Why own Sealed Letters

Sealed Letters: Letters and documents for the people you love, encrypted on Walrus and released by a Seal rule on Sui if you go quiet. Using someone else's version means their rules, their brand and their revenue. Owning Sealed Letters means it is deployed under your wallet, carries your name, and every customer, partner and result builds your track record instead of theirs.

What’s stopping you?

“I am not technical.”

Sealed Letters arrives deployed with a guide. Running it is settings and sharing links, not code. If you get stuck, we help you ship it.

“What if nobody uses it?”

Start with ten people you already know. The first move below takes under an hour and tells you fast whether people care.

“I do not have time.”

Each step is sized in minutes. Most owners spend an hour a week, and the app does the repetitive part.

“Will it make me money?”

Nothing is guaranteed. The playbook gives you a clear path and honest numbers, and you decide how far to take it.

The million-dollar ladder

Charge the people who get the most value from Sealed Letters: a monthly plan for groups or teams, plus setup fees for anyone who wants it done for them.

$100

$1,450

$11,700

$78,000

First harbour

5 customers

$20 a month

Steady trade

50 customers

$29 a month

Known name

300 customers