> For the complete documentation index, see [llms.txt](https://docs.infrastructure.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.infrastructure.finance/build/smart-contracts.md).

# Smart Contracts

The USD.infra Vault is implemented on Solana and is designed to handle mint + burn flows, vault accounting, and programmatic yield distribution based on explicit rules.

## **Contract surfaces:**

* Mint/Redeem (USD.infra): stablecoin entry flow and 1:1 mint path, paired with reserves reporting. 
* Vault contracts (sUSD.infra): deposit USD.infra → receive sUSD.infra. Vault accounting for participation in blended vault performance.
* Distribution logic: yield rules, fee deductions, and distribution events.
* Redemption logic: sUSD.infra → USD.infra protocol redemptions at the published exchange rate, settled from the liquidity sleeve, subject to verification, dynamic exit fees, liquidity-floor protections, circuit breakers, and queue ordering when the liquidity floor is reached.
* Liquidity management logic: The Vault adjusts redemption fees based on liquidity-sleeve utilization, enforces the circuit breaker, and may use available liquidity for qualifying DEX purchases of sUSD.infra when market price falls below exchange rate net of the applicable exit fee.

## **Upgradeability**

The USD.infra Vault touches real capital and real assets. Rollouts are to be staged, conservative, and paired with transparent reporting (Deal Explorer + reserves + Vault state) so users can verify system health without relying on trust.