FairPicker · Provably Fair Raffle Guide
What is a Provably Fair Raffle?
A Picker Selection Guide
Anyone running a giveaway eventually hits the same wall: how do you prove the draw wasn't rigged? A provably fair raffle picker answers that mathematically — and this page walks through what makes one provably fair, and how to tell a real raffle generator apart from a simple random name picker.
1. What is a provably fair raffle picker?
A provably fair raffle picker is built so the entire draw can be independently verified. The host can't quietly re-roll until they get a winner they like, and any participant can reproduce the result themselves with the same inputs.
The pattern is well known in online gaming and crypto, where it's called Provably Fair. FairPicker brings the same standard to Instagram, YouTube, and comment-thread giveaways: every draw ships a hash-sealed integrity certificate that anyone — including a skeptic in the replies — can check on their own.
2. Provably fair vs. a plain random picker
They look similar from the outside. The guarantees are not the same.
| What | Plain random picker | Provably fair picker |
|---|---|---|
| Tamper resistance | Trust the host | Cryptographically impossible |
| Reproducible result | No way to check | Anyone with the seed can reproduce |
| Proof of draw | A screenshot | Auto-issued integrity certificate |
| Re-roll prevention | None | One draw per URL, enforced |
3. The math behind it — SHA-256
FairPicker uses SHA-256 — the same hash function that underpins Bitcoin. Just before the draw, the server generates a Server Seed and the host supplies a Client Seed. The two are combined and hashed; that hash decides the winner order.
- The Server Seed is generated at draw time and includes a nanosecond timestamp.
- The Client Seed is supplied by the host, so the server cannot know the result in advance.
- The final SHA-256 hash is locked into the certificate — it cannot be edited later.
- Anyone can recompute the hash from the same inputs and verify the result.
4. How to evaluate a raffle picker
Plenty of tools call themselves “fair.” Use this checklist to tell which ones actually are.
- Verifiable algorithm — does it use a standard hash like SHA-256, and publish both the inputs (seeds) and the output (hash)?
- Integrity certificate — does every draw ship with a self-contained proof a third party can read?
- No silent re-rolls — is there a structural guarantee that the host can't keep drawing until they like the result?
- Privacy-respecting — are entrant names masked at collection time, instead of stored raw on the server?
5. What makes FairPicker different
- Free up to 300 entries — small giveaways run at no cost, certificate included.
- No sign-up — enter an email, start a draw.
- Multi-source — Instagram, YouTube, comment threads, and Excel files in one tool.
- Instant integrity certificate — every web certificate is free; paid draws also produce a printable PDF and a 4:5 social image.
- Privacy by default — Excel uploads are masked in the browser before they leave the device, and social-media comments are processed in server memory only.
Running a giveaway?
Start a provably fair draw now. Free for up to 300 entries — no sign-up needed.
Start a free fair draw →Related: 5 signs of a rigged giveaway