Help & Documentation

Learn how to run provably fair giveaways with Randomify

Getting Started

Create your first giveaway

How It Works

The provably fair algorithm

FAQ

Common questions answered

Getting Started

1

Connect Your Social Account

Before creating a giveaway, connect your Facebook or Instagram account. Go to Settings and click "Connect" next to Facebook. You'll need to authorize Randomify to access your pages and posts.

Note: We only request permissions to read comments on your posts. We never post on your behalf.

2

Create a New Giveaway

From your Dashboard, click "Create Giveaway". Fill in the details:

  • Title: A name for your giveaway (e.g., "Summer Giveaway 2026")
  • Platform: Select Facebook or Instagram
  • Post URL: The link to your social media post where people comment to enter
3

Activate Your Giveaway

Once your giveaway is set up, activate it to start collecting participants. When you activate:

  • A cryptographic commitment is generated (the "server seed hash")
  • Comments from your post are imported as participants
  • The giveaway becomes publicly viewable
4

Close & Draw

When you're ready to pick a winner:

  1. Close the giveaway to stop accepting new entries
  2. Click "Start Draw" to initiate the winner selection
  3. Watch the animated reveal as a winner is randomly selected
  4. Share the verification link with your audience

How It Works

The Provably Fair Algorithm

Randomify uses a commit-reveal scheme to ensure winner selection is truly random and verifiable. Here's how it works:

1. Commitment Phase

When you activate a giveaway, we generate a secret random seed and publish its SHA-256 hash. This "commits" us to a specific value without revealing it. The hash is shown on your giveaway page.

2. Collection Phase

Participants are collected from your social media post. Each unique commenter is assigned a position in the list based on their platform user ID (sorted alphabetically for consistency).

3. Draw Phase

When you draw a winner, we combine the server seed with a hash of the participant list. This creates a "final seed" that determines the winner index using the Mulberry32 algorithm.

4. Verification

After the draw, all data is published: the original seed, participant list, and winner index. Anyone can verify that the seed matches the original commitment and that the winner was correctly calculated.

Technical Details

Hash Algorithm

SHA-256

PRNG Algorithm

Mulberry32

Seed Format

64-character hex string

Participant Sort

Alphabetical by author ID

Giveaway Lifecycle

1

Draft

Setting up details

2

Active

Collecting entries

3

Closed

Ready for draw

4

Completed

Winner selected

Status Actions

  • Draft → Active: Generates commitment, starts importing participants
  • Active → Closed: Stops accepting new entries, enables draw button
  • Closed → Completed: Automatically set after drawing a winner

Frequently Asked Questions

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