Provably fair prize drawsa kwiboo service  /  Sealed

We don't pick the winner.
We can't. Here's the maths

Every draw is committed before entries open and its winner decided by public randomness nobody controls. When it closes we reveal the proof, so anyone can check the result for themselves and no one has to take your word for it.

Keep your websiteLive in a weekNo cut of entries
Try it: a real draw, right hereEntries open
1 Commit
2 Draw
3 Reveal
Right now, entries are open.The winning entry is already sealed by a secret that nobody can see, not you, not us. All anyone can see is the seal, a fingerprint of what's inside.
The seal, published publiclySHA-256 of the sealed value
What's inside the envelope
Sealed until entries close
Public randomness (drand)stands in for the beacon
How many entries in this draw
Committed before entries closeRandomness nobody controlsRevealed and verifiableCheck the maths yourselfCommitted before entries closeRandomness nobody controlsRevealed and verifiableCheck the maths yourself
4×

Every draw can be checked independently, by entrants, partners, regulators and you.

<1s

How long it takes anyone to re-verify a result, right in their browser.

0%

Of your entry revenue that we take. A flat fee for the platform, nothing else.

1 wk

Typical time from first call to running your first sealed draw.

Commit. Draw. Reveal.

Fairness isn't a promise here, it's the order of operations. The winner is locked in before entries close, decided by randomness we can't predict, and revealed so anyone can retrace every step.

Step one · Commit

We seal a secret

When the draw is created, before a single entry exists, we generate a secret seed and publish only its SHA-256 fingerprint. The seal is public; the seed stays hidden, even from us. Change it later and the fingerprint won't match.

Step two · Draw

Randomness nobody owns

A future drand round is pinned when the draw is created. Its random value doesn't exist until after entries close, and no single party can predict or fake it. At draw time it's mixed with the sealed seed to pick the winning entries.

Step three · Reveal

We open it in public

When the draw runs, the seed is revealed inside a signed certificate. Anyone can confirm the fingerprint still matches the seal and re-run the exact same maths to reach the exact same winners.

What your entrants see

One link ends
the argument

Every draw has a public certificate and a verifier page that needs no login. Your entrant opens it, the fairness checks run in front of them in the browser, and the result speaks for itself. No account, no jargon, no asking you to prove anything.

  • Public page, works on any phone, no sign-in needed
  • Shows the seal committed before entries opened
  • Re-runs the selection and confirms it matches
  • Checks our signature against a published public key
sealed.app/verify/A7F3
Draw #A7F3 · Range Rover Sport
Closed 14 June, 8:00pm · 5,000 entries
This draw was fairThe seal matches and the signature checks out. The winner was fixed before entries opened.
Winning entry#3,812
Seal committed8f14e45f…c2a9
drand round4,812,901
Checked by you, just now✓ Match

“How do we know it's not your mate who won?”

Every competition gets asked this. Right now the only answer most operators have is “trust us”. Here's a better one, and it pays you back.

01

People enter more

Doubt is the biggest reason someone closes the tab without paying. When entrants can check the draw themselves, the hesitation disappears, and it compounds across every competition you run.

02

Complaints end in seconds

Instead of a long back-and-forth in your inbox or under a Facebook post, you send one link. They see the maths, they check it themselves, the conversation's over.

03

You've got a paper trail

Every draw is recorded, timestamped and signed. If a partner, a payment provider or a regulator ever asks how winners are chosen, the evidence already exists, you don't have to reconstruct it.

04

It's a reason to choose you

In a crowded market where every competition looks the same, being the one that can prove itself is a genuine difference worth putting on your homepage.

Built for anyone who picks a winner

If money or reputation rides on the result being fair, the same proof applies.

Prize competitions

Cars, cash and tech draws where entrants are paying and trust is the whole business.

Charity raffles

Where donors need to see their money was handled properly, and trustees need an audit trail.

Brand giveaways

Social and retail promotions where a rigged-looking result becomes a PR problem fast.

Everything for the draw nothing you already have

Your website, your payments, your branding, your entrants all stay exactly as they are. We only handle the bit where a winner is chosen, and proven.

01

The sealed draw

The commit, the reveal and the winner: the core of the whole thing.

02

A public verifier

Anyone can re-run a draw's certificate on a no-login page and confirm the result. Send the link and you're done.

03

Randomness you don't control

Winners are decided using a public drand round pinned in advance, so you couldn't rig it even if you wanted to.

04

Multiple winners and tiers

Runners-up, tiered prizes and multiple winners from a single sealed draw are all covered.

05

Scheduled draws

Recurring monthly, weekly or daily draws, or a one-off window, run automatically at their set time.

06

Signed certificates

Every draw produces a signed certificate as PDF and JSON, ready to hand to anyone who asks.

07

Results the moment they're final

As soon as a draw completes, its winners and signed certificate are ready to pull from the API.

08

A permanent audit log

Every draw event is recorded and locked once written, so nothing can be quietly edited later, including by us.

09

Setup help

We'll get your first draw running with you. Most people are live the same week.

What we can't do, by design

The whole point is to take the decision out of human hands. So there are things Sealed simply cannot do.

We can't

  • Predict the winning entry before the draw
  • Change the sealed seed once it's committed
  • Influence or predict the drand value
  • Quietly re-run a draw until we like the result
  • See or favour any individual entrant

We always

  • Publish the seal before entries close
  • Pin the drand round in advance
  • Reveal the seed in full after the draw
  • Offer independent, in-browser verification
  • Keep a permanent, timestamped record

The difference on the day it matters

What actually changes when someone questions your draw.

When an entrant asks…
Without Sealed
With Sealed
“How was the winner picked?”
You explain your process
They check it themselves
“Could you have changed it?”
“You'll have to trust us”
Mathematically, no
“Prove it was decided before I entered”
No way to show it
Committed, timestamped
A regulator asks for records
Reconstruct from spreadsheets
Export the certificate
Accusation posted publicly
Days of argument
One link

From first call to first sealed draw

No migration, no rebuild, no downtime on your existing competitions.

Day one

The demo

Fifteen minutes. We seal a draw, reveal it and break it in front of you.

Day two

Connect it

Whoever looks after your site hooks it up. We sit on the call and help.

Day three

Test run

A dummy draw end to end, so you've seen the whole flow before it's real.

Week one

Go live

Your next competition runs sealed, with a check-it-yourself link for entrants.

For your developer

The technical
version, briefly

A commit-reveal seed mixed with drand entropy and a deterministic selection algorithm, exposed as a REST API. Create a draw, submit entries, run it, and get back a result anyone can reproduce.

  • A handful of endpoints, documented in OpenAPI / Swagger
  • External entropy from a drand round, pinned when the draw is created
  • Two ways in: an operator login, or scoped X-Api-Key keys for machines
  • A published verification spec and public key, so nobody has to trust our servers
// Create the draw, committing the seed before entries POST /draws { "prizeTiers": ["£5,000"] } // → seed commitment + pinned drand round { "seedCommit": "8f14e45f…c2a9", "drandRound": 4812901 } // Run it once the entry window has closed POST /draws/:id/run // → winners, revealed seed, signed certificate GET /draws/:id/winners GET /draws/:id/certificate

Stop saying
“trust us”

Fifteen minutes is enough to see a draw sealed, revealed and checked. Bring your hardest question about fairness and we'll answer it live.

  • A live sealed draw, start to finish
  • How it fits your existing website and payments
  • What your entrants would see and check

Protected by reCAPTCHA. No sales pressure: fifteen minutes, your questions, a live sealed draw.