Drawpool

What we built

DrawPool is a no-loss savings pool on OPN Chain.

Users deposit tUSDC into a shared pool, keep 100% of their principal withdrawable at all times outside the short draw window, and compete only for the pool's accrued yield. At each draw, one depositor wins the entire yield prize, with odds proportional to deposit size.

The core system is built from three contracts:

• DrawPool: principal accounting, deposits, withdrawals, draw lifecycle, and weighted winner selection
• FinalityRandomness: commits each draw to a future OPN block and derives entropy from the finalized block hash
• SponsoredYieldSource: testnet yield adapter that simulates continuous yield via a sponsor-funded reserve

Why this matters

Prize-linked savings only works if users can trust two things:

1. their principal is safe
2. the winner selection cannot be manipulated

DrawPool addresses both.

Principal is never put at risk in the raffle. Only the yield is awarded. On the randomness side, this design is specifically built around OPN's instant finality. The system commits to a future block before the outcome is known, then uses that finalized block hash as the entropy source. That makes the draw transparent, auditable, and much harder to game than an off-chain raffle flow.

How it works

1. Users deposit tUSDC into the pool
2. Yield accrues in the yield source and becomes the next prize
3. Anyone can start a draw once the interval expires
4. The protocol commits to a future OPN block
5. Once that block is finalized, the block hash is used to derive randomness
6. A winner is selected on-chain with balance-weighted odds
7. The full yield prize is awarded and auto-compounded into the winner's balance

What is live today

The project is deployed on OPN testnet and already has live on-chain activity, including deposits and completed draw infrastructure.

Live demo: https://drawpool.xyz

Core contracts in this submission:

• DrawPool
• FinalityRandomness
• SponsoredYieldSource

MockUSDC exists only as testnet scaffolding so reviewers can interact with the product without needing a bridged stablecoin.

Why OPN

This design is not chain-agnostic glue.

DrawPool depends on committing to a future block and later using its finalized hash as a fairness anchor. On OPN, fast blocks and instant finality make that flow practical for users and credible for reviewers. The short commit-to-settle window feels natural, and the entropy source is publicly verifiable on-chain.

Current scope and next step

This version is a testnet MVP focused on proving the product loop:

• no-loss principal
• balance-weighted prize draws
• on-chain, publicly auditable randomness
• clean user-facing demo

The next step would be replacing the sponsored testnet yield adapter with a production yield source while keeping the same pool and randomness architecture.