Sapien Vault

The Sapien Vault is the onchain economic-security layer for Proof of Quality (PoQ). You can deposit SAPIEN and receive vault shares (vSAPIEN). Locking stake as collateral for validation work is optional and at your sole discretion if you choose to participate as a validator. When you do lock, the vault escrows that collateral and applies unlock or slash outcomes decided by the offchain PoQ engine.

It does not score contributions or run consensus onchain. It only holds assets and enforces lock / unlock / slash instructions.

What it is

How it fits PoQ

1. Anyone can deposit SAPIEN into the vault and receive vSAPIEN shares.
2. If you opt in as a validator, after shares mature past the configured deposit age you may call lockStake — optionally, at your sole discretion — to put collateral at risk for validation work.
3. The offchain PoQ engine evaluates outcomes and, when needed, calls:
   • unlockStake — reduce locked amount; value becomes withdrawable again
   • slashStake — burn shares so the validator loses the slashed value
4. The validator withdraws or redeems whatever remains unlocked and matured.

In the product API, validators who choose to participate on staked projects typically lock stake through the staking / batch-lock flow before claiming validations. The vault is the onchain source of truth for locked vs available balance.

Stake model

Each address has one stake account:

lockStake is permissionless for the holder and is never automatic — you choose whether and how much to lock. Unlock and slash are engine-only — locked stake cannot be exited without the engine (or a slash).

Roles

Admin can pause the vault to halt a misbehaving engine, and can revoke ENGINE_ROLE. Pause stops deposits, withdrawals, transfers, and lock/unlock/slash paths that respect pause.

Deposit age

To resist flash deposit → lock → exit patterns, the vault can require shares to age before they count as available for lock, transfer, or withdraw.

• Configured by admin (minDepositAge, capped at 7 days).
• Enforced per share cohort (tranche), not as a single global timer per user.
• Fresh deposits create immature tranches; once aged, shares fold into the matured bucket.
• Use depositAgeStatus(user) (or maturedShares / pendingShares) when integrating.

When minDepositAge is 0, deposits are immediately mature.

Deployments

Canonical deployment JSON lives in the sapien-contracts repository under deployments/.

Integrator notes

• Prefer ERC-4626 preview* and max* helpers before submitting txs; they reflect pause, locks, and deposit age.
• Locked stake reduces maxWithdraw / maxRedeem.
• Slashing burns shares without removing underlying SAPIEN from the vault, so remaining stakers' share value appreciates. Index both slash amount and shares burned.
• Engine liveness matters: if unlocks stop, locked stake stays locked until the engine resumes (or ops intervene via pause / role revoke — which still does not auto-unlock existing locks).

Further reading

• Github Repo: sapien-contracts
• Contract deep dive: docs/SapienVault.md in sapien-contracts
• OpenZeppelin ERC-4626

Security audit

Quantstamp audited SapienVault. Read the final report:

QS SapienVault Final Report — June 2026 (PDF)