What is RAI Dollar?

RAI Dollar is an immutable stablecoin lending protocol running on Ethereum. You lock up crypto collateral (ETH, wstETH, rETH, WBTC, and other supported assets) and mint RD, a USD-denominated stablecoin. You can repay and withdraw your collateral at any time.

RD targets $1. The protocol has built-in mechanisms, redemption arbitrage and adaptive interest rates, to keep market price close to $1. See How it stays stable for the full picture.

What you can do with it

• Borrow: open a "trove" against your collateral, mint RD, hold or use it however you like, repay later. There is no fixed-term loan and no fixed schedule, your only obligation is to keep your collateral ratio above the branch's minimum collateral ratio (MCR — 110% on WETH, higher on other branches).
• Hold or trade RD: standard ERC-20. Acquire it by borrowing, by buying on a DEX, or by being paid in it.
• Redeem RD for collateral: any holder can exchange RD for collateral at par, less a small fee. This is the mechanism that puts a floor under the price.
• Earn: deposit RD into a Stability Pool to absorb liquidations (and earn collateral + FEE rewards) LP into supported pools. Earn FEE(read more below).

Lock collateral to mint RD, then put it to work: sell or spend it, deposit it in a Stability Pool to earn from liquidations, or LP it for FEE + RD. Repay your debt at any time to unlock your collateral.

What makes the design different

• Immutable and ungoverned. No owner, no admin keys, no governance, no upgrade path. Nobody can censor or blacklist a user, change a parameter, or hand-settle a crisis. When a branch fails it winds down on a fixed on-chain schedule, not by a committee's decision. See Risks.
• Stability under crisis. Uses a novel blend of proven mechanisms from Liquity and Reflexer, as well as new mechanisms, to provide market stability under all possible stress states. See How it stays stable.
• Self-repairing bad debt. If a branch ever ends up undercollateralized, the protocol repairs its own balance sheet: a slice of every healthy-branch redemption fee, plus half of the FEE-staker interest share, is routed to that branch's payDebt until it is solvent again. No bailout, no admin top-up. See Fees.
• Optimal fee routing. Borrow interest is not split on a fixed schedule. PI controllers continuously route it to wherever it is needed most, sending more to a thin Stability Pool or to shallow LP liquidity, so incentives stay balanced. See Fees.

Architecture

Every collateral lives in its own isolated branch — its own troves, Stability Pool, and price feed — so trouble in one collateral cannot spread to another. One coordinator routes what must be shared, and one controller steers one rate and one par for the whole system.

The contract-level topology and message flows are in Architecture.

Two tokens

• RD: the stablecoin. Minted only by the protocol when collateral is locked; burned when debt is repaid or redeemed.
• FEE: the protocol's value-capture token. Holders stake it to earn a share of borrow interest, paid in RD. See FEE staking.

Where to go next

• New to the protocol? Read How it stays stable and the FAQ.
• Ready to borrow? Start with Open a trove.
• Holding RD already? See How RD stays near $1 and Redemption.
• Want to dig into mechanics? Start at Architecture.